Computer Has a Black Screen (BSOD)

Computer Black Screen Of Death can be frustrating Sometimes

There are two types of computer black screens that can appear in Windows. 

  • One where the computer will not boot up but you have a beep sequence sounding to let you know what the problem could be,
  • The other has nothing at all. No beeps, no cursor, no logo screen, and no choice to boot to safe mode or access the bios.
  • If your computer will not boot up and you get a beep sequence, that doesn't mean you are good to go however, it is a step in the right direction towards solving this problem. 
This is a message from your computer that can be understood by looking up your BIOS(the brand) beep code.
 For example you may have an Award Bios, Ami Bios, Phoenix BIOS, Compaq, Dell, or Acer Bios. This list goes on and on.  You can search for Bios beep codes in Google.
 Here is an example of results in Google search Search results for “bios beep codes”

If you heard a single beep, then the computer posted, and the CPU is OK. POST= Power On Self Test  is procedure the computer goes through on starting to ensure all is well.

When your computer has a black screen in windows, and absolutely nothing else, this is where the challenge begins. Sometimes the fans and the CPU seems to be running.

It would be good to have a replacement part for basically any computer component at your fingertips.  If you do not have these tools then you will need to try and find the errors manually.

Common things that can happen when your computer has a black screen in Windows:

(1). When the computer is booting up, it sound like it is booting as the CPU fan is running and the lights are on. 
It also finds the CD ROM but it won’t boot from a CD either.

(2). Sometimes when you have a computer black screen on startup and the power switch light will be green and then turns to orange or amber.
Everything seems to be running but you can’t see anything on the screen, not even a flashing cursor. Your black screen in Windows has occurred before the Windows logo screen.

Some common causes of a computer black screen in Windows:

HERE ARE SOME BASIC CAUSE AND SOLUTION

(1). Starting Windows Without Taking note of the displayed error:
If you see the screen that tells you your computer had an error, do not choose to start normally, choose to start in safe mode now. See what is safe mode. This is your chance to go the safe way. Many people rush and press to start Windows normally and sometimes this causes a serious problem.

(2). Where is your Monitor plugged in? “My PC screen is black”

The first and most obvious reason for a computer appearing to run but you cannot see the video is the monitor. A common mistake is to plug the monitor into the on-board video plug when you actually have a PCI or AGP video card installed.
 Trust me I have done this myself. Simply move the plug to the correct position. If you see two blue monitor plugs at the back of the computer or even a blue plug and a HDMI port then try using a different plug.

Obviously you should also check to see if the monitor plugged is actually in firmly. It could have been knocked out if it was not correctly positioned in the first place.

(3). Failing Display adapter or video card can cause a black screen in windows:

Most of the time you can tell if your computer video card is deteriorating by seeing little tell tale signs. Lines appearing or flashing can sometimes occur, however sometimes nothing happens at all. You might turn your computer on and have the dreaded black screen. You can try removing your video card and using onboard video, or replacing the video card to see if that is the problem.

(4). Plugged PC into a different monitor or even a TV:
 When the screen resolution is not compatible which actually gives the computer are serious black screen.

 Restart and press F8. This will take me to the the menu where you will choose enable VGA mode or something similar.

(5).The next reason the computer will not boot up is RAM…or memory:


This can be the cause when your computer has a black screen in Windows.

If your memory is not seated properly, is damaged, or even absent altogether, this can cause a black screen.
If you have no memory installed at all, some computers make no sounds and just show a black screen on startup.
When your computer gets a black screen only sometimes, it usually means your ram is on the way out For example if you boot your computer and it doesn’t work, then go back an hour later, and it does work, your memory is playing up. 

You can try taking the ram out, gently cleaning it with an antistatic cloth, and replacing it. This may solve your problem. If it does not, then you should try running your computer with another compatible stick of ram installed.

(6). Black screen on startup with an amber flashing light
A flashing amber light along with your black screen on startup can be a few things.

  • Not enough power getting to the motherboard.
  • A dead power supply.
  • A bent pin or shorted out USB port causing a problem.
  • Computer black screen after installing new hardware
Often when computer users install hardware in order to upgrade their own computers they run into problems. If you have just performed an upgrade and then get a black screen, the answer is obvious.
Some hardware components may not be compatible with the others in your system. And of course there is always the risk of static electricity damaging your components when you are not an experienced computer repair person.

You might just be installing a new piece of RAM but the best way to troubleshoot this is to go back to where you started from. Always start from the beginning. If your computer was working and you installed something, then take it back out. Think about what you are doing and try again.

This has nothing to with getting a black screen in Windows, as sometimes you have not even installed Windows yet. The hardware must be compatible together and also must be installed correctly.

(7). Leaving a bootable usb flash drive connected to your computer

Yes this can confuse your computer and it won’t know where to boot up. When your computer has a black screen on startup from doing this and you realize this is the problem and remove the USB, the computer just continues to boot normally..this sometimes happens because a computer sometimes recognizes a USB as a CD drive and tries to boot to it. This is the easiest cause of a black screen in Windows as you can simply just take it out and restart your computer.

keyboard. This is why having a black screen in Windows as a crazy amount of causes and solutions. I really did not expect this one to come out of the woodwork.

Corrupted User Account 

If you have logged into Windows, so you actually saw the login screen, then logged into Windows, this can mean a few different things. One is that it can be a corrupted user account. In this case it would be handy to have another user account to login to. Then you would be able to tell straight away if that was the problem or not. If you can log into another account you will be able to access the corrupted user account through the main hard drive which is usually called C: drive. You will see a folder called “users” and then there will be another folder for the actual username.

If your computer has black screen but you can see one small flashing cursor, I see this as a good sign! It usually means your computer is ok to be formatted. It can also mean that you should try to repair the boot sector first. 

How to repair a damaged boot sector.
Simply Insert your Bootable disc or drive then boot from that disc / drive once it load the interface simply choose the "Repair option"

There are many other reason you can have a Black Screen Of Death on Your PC, above are the common cause. “Happy DIY”

(8). Corrupting the Boot Sector:

A black screen on startup can be of so many things! I have learned this lesson the hard way. Never turn off the computer when it is half way through the boot procedure. Even when it is taking forever, or having a major problem you must let it run through if possible. Interrupting it once may be ok, but twice or three times is a no no. After you have carelessly restarted and shutdown a few times the black screen may appear. But this time it may be beyond repair for the average computer user.

Here are some other cause: 

Your CPU is not correctly seated
If your computer has a black screen after transporting one place to another, this is the first place I look. Transporting a working computer, and then not working with a black screen = dislodging the CPU. You can fix this easily by removing the CPU fan and carefully replacing it back in its spot. You may also have to replace some thermal paste between the cpu and heat sink as it stops the cpu from overheating. Be very careful not to bend any pins when dealing with your computer CPU.

Keyboard Faulty
This one surprised me because when there is a problem with the keyboard the computer still boots and says that there is no keyboard detected on the screen. Well this didn’t happen for me. I had a keyboard with a bent pin on the cable, so when it was plugged into the computer, it just plugged in normally. Then the computer black screen on startup appeared, you could here it starting up but no posting beeps, no display, nothing. I even swapped monitors around until finally I tested the keyboard and found the bent pin. I never thought to look there because of the usual default message that appears on the screen when there is something wrong with your 
keyboard. This is why having a black screen in Windows as a crazy amount of causes and solutions. I really did not expect this one to come out of the woodwork.

Corrupted User Account 
If you have logged into Windows, so you actually saw the login screen, then logged into Windows, this can mean a few different things. One is that it can be a corrupted user account. In this case it would be handy to have another user account to login to. Then you would be able to tell straight away if that was the problem or not. If you can log into another account you will be able to access the corrupted user account through the main hard drive which is usually called C: drive. You will see a folder called “users” and then there will be another folder for the actual username.

If your computer has black screen but you can see one small flashing cursor, I see this as a good sign! It usually means your computer is ok to be formatted. It can also mean that you should try to repair the boot sector first. 

How to repair a damaged boot sector.
Simply Insert your Bootable disc or drive then boot from that disc / drive once it load the interface simply choose the "Repair option"

There are many other reason you can have a Black Screen Of Death on Your PC, above are the common cause. “Happy DIY”



Port Numbers and There usage


PORT NUMBER AND THEIR USES


There are 65,535 Port Numbers of that  0-1023 are well known port numbers, 1024-49,151 are Registered 49,152-65,535 are Dynamic or private ports.

Below are some of the well known ports:-
Port                                                     Description status
0/TCP,UDP                                                          Reserved; do not use (but is a permissible source port value)
1/TCP,UDP TCPMUX                                       (TCP port service multiplexer) Official
5/TCP,UDP                                                          RJE (Remote Job Entry)
7/TCP,UDP                                                          ECHO protocol
9/TCP,UDP                                                          DISCARD protocol 
11/TCP,UDP                                                       SYSTAT protocol
13/TCP,UDP                                                       DAYTIME protocol
17/TCP,UDP                                                       QOTD (Quote of the Day) protocol
18/TCP,UDP                                                       Message Send Protocol 
19/TCP,UDP                                                       CHARGEN (Character Generator) protocol 
20/TCP FTP –                                                    Data Port 
21/TCP FTP -                                                     Control (command) port 
22/TCP,UDP                                                       SSH (Secure Shell) - used for secure logins, file transfers (scp, sftp) and port forwarding 
23/TCP,UDP                                                       Telnet protocol - unencrypted text communications 
25/TCP,UDP SMTP                                            Used for e-mail routing between mail-servers E-mails 
26/TCP,UDP RSFT                                             A simple FTP-like protocol 
35/TCP,UDP                                                       QMS Magicolor 2 printer 
37/TCP,UDP                                                       TIME protocol 
38/TCP,UDP                                                       Route Access Protocol 
39/TCP,UDP                                                       Resource Location Protocol 
41/TCP,UDP                                                       Graphics
42/TCP,UDP                                                       Host Name Server 
42/TCP,UDP                                                       WINS [1] 
43/TCP                                                                WHOIS protocol 
49/TCP,UDP                                                       TACACS Login Host protocol 
53/TCP,UDP                                                       DNS (Domain Name System) 
57/TCP                                                                MTP, Mail Transfer Protocol
67/UDP                                                               BOOTP (BootStrap Protocol) server; also used by DHCP (Dynamic Host Configuration Protocol)
68/UDP                                                               BOOTP client; also used by DHCP 
69/UDP                                                               TFTP (Trivial File Transfer Protocol) 
70/TCP                                                                Gopher protocol 
79/TCP                                                                Finger protocol 
80/TCP                                                                HTTP (Hypertext Transfer Protocol) - used for transferring web pages 
81/TCP                                                                HTTP Alternate (Hypertext Transfer Protocol) 
81/TCP                                                                Torpark - Onion routing ORport 
82/UDP                                                               Torpark - Control Port Unofficial
88/TCP                                                                Kerberos - authenticating agent
101/TCP                                                             HOSTNAME
102/TCP                                                             ISO-TSAP protocol 
107/TCP                                                             Remote Telnet Service
109/TCP                                                             POP, Post Office Protocol, version 2
110/TCP                                                             POP3 (Post Office Protocol version 3) - used for retrieving E-mails 
111/TCP                                                              UDP SUNRPC protocol 
113/TCP                                                              Identity - old server identification system, still used by IRC servers to identify its users
115/TCP                                                              SFTP, Simple File Transfer Protocol
117/TCP                                                              UUCP-PATH 
118/TCP,UDP                                                    SQL Services 
119/TCP                                                              NNTP (Network News Transfer Protocol) - used for retrieving newsgroups messages 
123/UDP                                                             NTP (Network Time Protocol) - used for time synchronization 
135/TCP,UDP                                                    EPMAP (End Point Mapper) / Microsoft RPC Locator Service 
137/TCP,UDP                                                    NetBIOS NetBIOS Name Service 
138/TCP,UDP                                                    NetBIOS NetBIOS Datagram Service 
139/TCP,UDP                                                    NetBIOS NetBIOS Session Service 
143/TCP,UDP                                                    IMAP4 (Internet Message Access Protocol 4) - used for retrieving E-mails 
152/TCP,UDP                                                    BFTP, Background File Transfer Program
153/TCP,UDP                                                    SGMP, Simple Gateway Monitoring Protocol
156/TCP,UDP                                                    SQL Service 
158/TCP,UDP                                                    DMSP, Distributed Mail Service Protocol
161/TCP,UDP                                                    SNMP (Simple Network Management Protocol)
162/TCP,UDP                                                    SNMPTRAP
170/TCP                                                              Print-Server
179/TCP                                                              BGP (Border Gateway Protocol) 
194/TCP                                                              IRC (Internet Relay Chat) 
201/TCP,UDP                                                    AppleTalk Routing Maintenance
209/TCP,UDP                                                    The Quick Mail Transfer Protocol
213/TCP,UDP                                                    IPX 
218/TCP,UDP                                                    MPP, Message Posting Protocol
220/TCP,UDP                                                    IMAP, Interactive Mail Access Protocol, version
3
259/TCP,UDP                                                    ESRO, Efficient Short Remote Operations
264/TCP,UDP                                                    BGMP, Border Gateway Multicast Protocol
311/TCP                                                             Apple Server-Admin-Tool, Workgroup-Manager-Tool
318/TCP,UDP                                                   TSP, Time Stamp Protocol
323/TCP,UDP                                                    IMMP, Internet Message Mapping Protocol
383/TCP,UDP                                                    HP OpenView HTTPs Operations Agent
366/TCP,UDP                                                    SMTP, Simple Mail Transfer Protocol. ODMR, On-Demand Mail Relay
369/TCP,UDP                                                     Rpc-2-portmap
371/TCP,UDP                                                     ClearCase albd 
384/TCP,UDP                                                     A Remote Network Server System
387/TCP,UDP                                                     AURP, AppleTalk Update-based Routing Protocol
389/TCP,UDP                                                     LDAP (Lightweight Directory Access Protocol) 
401/TCP,UDP                                                     UPS Uninterruptible Power Supply 
411/TCP                                                              Direct Connect Hub port 
412/TCP                                                              Direct Connect Client-To-Client port 
427/TCP,                                                              UDP SLP (Service Location Protocol) 
443/TCP                                                              HTTPS - HTTP Protocol over TLS/SSL (encrypted transmission) 
444/TCP,UDP                                                    SNPP, Simple Network Paging Protocol
445/TCP                                                              Microsoft-DS (Active Directory, Windows shares, Sasser worm, Agobot, Zobotworm) Official
445/UDP                                                             Microsoft-DS SMB file sharing Official
464/TCP,UDP                                                    Kerberos Change/Set password Official
465/TCP                                                              SMTP over SSL - CONFLICT with registered Cisco protocol Conflict
500/TCP,UDP                                                    ISAKMP, IKE-Internet Key Exchange Official
512/TCP                                                              Remote Process Execution