I have a problem with my PC, I searched online and in the posted threads but I couldn't find a solution, or I couldn't find an exact matching case to mine.

The PC is assembled and was working fine, until all of the sudden it shut down without any obvious reason, no software or hardware changes.

After switching it on again it wouldn't go to windows and instead displayed on the black screen that there is some system error (unfortunately i don't remember the exact error message). It kept giving this black screen with the error message for few times switching off and on and then it stopped giving signal to the monitor.

So now when I turn it on everything inside the case seems to work (I mean the CPU fan is working and also the graphics card, power supply..) but:

  • The monitor displays "no signal" and the power light remains yellow instead of turning green as usual.
  • The keyboard lights (num, caps, etc..) turn on then off again as when you usually turn on the PC, but after that they stay off and they don't respond anymore if I press any of them.
  • There is no beep sound at all coming out of the PC internal speaker.

I tried few things and I know the following are working fine:

  • Checked all the cables nothing is wrong.
  • We thought it might be the power supply but we replaced it and nothing changed.
  • The monitor is working fine we tried it on the laptop and we even tried another monitor.
  • The video card is not the problem we removed it and tried the mother board's internal graphic card but it didn't work either.
  • We made sure all stuff inside are placed correctly like the RAM and hard disk etc..

I think that's it, from my readings it seems to be either the mother board or the CPU? How can I tell which one exactly? Could it be something else that I missed?

Thank you for your time...

I would remove any add-in cards, remove the Hard Drive, remove any peripherals, and reset the CMOS using the jumper on the Mobo.

Is there graphics on the Mobo?

Are the reset jumpers shorted?

Hi CimmerianX thanks for your reply..

I reset cmos b4 but didn't work. I didn't actually try to remove the hard disk because I didn't know that this could be relevant to getting signal to the monitor, so you are saying if the problem is from the hard drive and i remove it then the monitor might show something?

Regarding the graphic card yes there is an internal one on the Mobo but we are using an external, both did not fix the problem..

I'm not at all saying that the hardrive is the cause, but when troubleshooting, you remove all possibilities. Whatever is left, no matter how improbable, must be the answer.

If you have a graphics card on the mobo, use it for now.

Boot the machine, and you should get activity. Even if there is no display. If hit reset button, do you see the activity "blip"?