My computer turns on but nothing appears on the screen

repair computer that turns on and has a black screen

This is what has happened to me on my nine year old PC. The computer starts up but nothing is visible on the screen. I explain how to diagnose the error to find out what is failing, since it seems to be a common error.

The failure usually comes from one of these 3 places:

  • The screen
  • RAM
  • Graphics card

Preliminary considerations

First of all check that you do NOT have a USB, cd, smartphone, watch, fitbit, or other hardware connected to the computer. If you have something connected other than a mouse, keyboard and speakers, remove it and try starting again. Many times we forget something connected and if we have the BIOS configured to boot from an external disk it tries to execute it and gives the error.

If you like this type of repair, check out this trick to unlock a smartphone with a broken screen.

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The screen

We check that the screen works. It sounds like bullshit, but it's something to be discarded. Since in the failure we discussed, the computer works, it starts up, so it could be that everything was working fine but the screen had been damaged.

Testing it is very simple, connect a laptop or other device that has HDMI or if the monitor has a television, try to see if it works. Normally we will get a No Signal message, and with that we already know that a screen error is ruled out.


the ram of our computer possible source of errors

If any RAM module you have connected is damaged or badly connected, because it has come out, because there is dirt and it does not make good contact, we can also find this problem.

Clean the dust, the ideal is with compressed air and if we get exquisite with an anti-static brush. But with a normal brush you will not have any problem either.

Change the slot modules. Try them one by one to see if they fail.

The graphics card or GPU

graphics card or GPU, graphics and display error

The next option is the graph. You have to remove it, clean the connections with a brush and test again if it works.

Before buying another graphic, ask a friend for an old one to make sure that it is really what is wrong.

How to fix the graph

my geforce 240 graphics card

Although it is not the objective of this article I leave some small indications.

If it is damaged, clean the fan and heatsink well, remove it and change the thermal paste. See if there is a component in bad condition that can be replaced or a bad solder.

And finally if we can't make it work we can consider doing reflowing which I will teach to do in another article.

Motherboard Error Diagnosis with Beeps

buzzer on motherboard

The motherboards have an error diagnosis with which they tell us what is not working. It can be seen with the LEDs on the power button, although the simplest thing is with the beeps, the sound it emits when there is a problem.

If everything goes well on our PC, a beep is heard and the computer continues to work.

If something fails, it beeps according to a sequence, 2 beeps, 2 long and one short, 3 beeps, etc. and with this we know which part of the computer is failing

Now, most people search the Internet for a sound diagnosis and on each page they find different meanings for the beeps. This is because it depends on the BIOS you have.

So the correct procedure is:

  1. Find out what motherboard you have. Looking at it, or because you have the box saved or some purchase invoice.
  2. Once you have it, download the Manual of your plate searching in Google (the model of your plate Manual filetype: pdf)
  3. Then find where the error code is. I look inside the pdf for the word "beep" so I usually find it in a few seconds.

In this way you ensure that the safe diagnosis that corresponds to your error

Sometimes, as is my case, the computer does not make any sound because it does not have a buzzer installed. Many plates have it integrated but others do not, it came in the box and I have it saved.

If the same thing happens to you, look for it, ask a friend for one or buy one that is always good to have on hand or leave it mounted on the PC. To know where to put it, look on the plate where it says buzzer.

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