Black Screen Error
Rarely do I come across a problem with a computer that I cannot diagnose, however when a computer has a black screen on boot it can stump me sometimes. I always try to trouble shoot the problem manually, without using those fancy programs, because I believe it is the only way to learn.
There are two types of black screens that can appear. One that will have a beep sequence sounding to let you know what the problem could be, and 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 you get a beep sequence, I am not saying it is good news, 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 A procedure the computer goes through on starting to ensure all is well.
When your computer has a black screen, and absolutely nothing else, this is where the challenge begins. Sometimes the fans and the CPU seems to be running.
When this happens to me, I have an instant advantage as I have a replacement part for basically any computer component at my fingertips.
Common things that can happen when your computer has a black screen:
- At boot 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.
- Sometimes the computer has a black screen and the power switch light will be green and then turns to orange or amber. Everything is running.
- Everything seems to be running but you can’t see anything on the screen, not even a flashing cursor.
Some common causes when your computer has a black screen at boot up:
Where is your Monitor plugged in?
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.
Failing Display adapter or video card can cause a black screen:
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.
The next reason is RAM…or memory: This can cause when your computer has a black screen.
If your memory is not seated properly (not in), is damaged, or even absent altogether, this can cause major problems.
- If you have no memory installed at all, some computers make no sounds and just show a black screen. Other computers go crazy and beep their head off. I am an expert at this one, as I build so my computers.
- 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.
If you plan to open your computer case and remove the ram please read these articles How to open a computer case safely and Upgrade Memory
Computer has a 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.
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 from doing this and you realize this is the problem and remove the USB, the computer just continues to boot normally..
Corrupting the Boot Sector.
I have learnt 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. How to repair a damaged boot sector by replacing the master boot record (MBR) in Windows XP
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.
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 had a black screen, 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.
Notes relating to your computer has a black screen:
- 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 by replacing the master boot record (MBR) in Windows XP
- Here is an error specific article about A black screen with a flashing cursor.
- Lets face it.. Having a black screen is a common symptom for so many problems.
If your computer has a black screen, please research your possible problem and be patient as fixing this error is usually left to the experts.
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