Need help diagnosing which part is faulty.

[timil]

I was using my PC one day when the screen went white for about 10 seconds, then it shut down. Upon attempting to restart, I get no display signal.

Before I start I'll just say this: I've tried resetting the CMOS, I've tried reshuffling the RAM, I've tried breadboarding the whole system and testing components one-by-one and I've even disconnected and reconnected the CPU.

As far as I can see, there are no odd looking caps on the motherboard, and I heard no bang nor smelt any burning when the crash happened. There is no burnt parts anywhere in the machine either.

I can't tell if my PSU or GPU is dead, and I don't have another PSU/GPU/PC or a multimeter to test with so I'm basically flying blind here - all I have is this one little clue which, if anyone on this forum with more expertise could decipher, might tell me which part is faulty:

If I start the computer without the video card connected (CPU, RAM, motherboard, CPU HSF, power supply, mouse and keyboard) the computer will boot normally and give 8 BIOS beeps which, if my assumption that the ASRock 970DE3 uses an AMI BIOS is correct, means there's a GPU error since the GPU is missing.

However, if I put the video card back in, I don't get any BIOS beeps at all and even more bizarrely, the mouse and keyboard don't light up during the boot process like they normally do. Why would the presence of the video card stop the mouse/keyboard from lighting up? And why are there NO error beeps when the video card is present? See, I figure that if the motherboard could tell the GPU is faulty, the BIOS would give some GPU related error beeps, and if the motherboard can't tell the GPU is faulty it should POST normally with a single beep. Why does the presence of the video card cause a complete absence of beeps?

This could indicate an inadequate power supply, but that also doesn't quite make sense. If the power supply has deteriorated to the point where it can no longer power the video card, why would it not, at the very least, be able to power it during the boot phase when the card only sips power? And to add to that, the GPU fans still spin, even with a hard drive, SSD, sound card and Wi-Fi card all connected.

I know testing the video card/power supply on another machine is the obvious solution, but I simply don't have access to any other machines or parts.

Here are my specs if that helps:

Phenom II X4 965 C2
ASRock 970DE3
G.Skill 2 x2GB DDR3-1600
Antec HCG-520
Gigabyte 7870

I've had the machine for about 3 years.

 

[Hamperking68]

By the sounds of thing the GPU is faulty. You need to replace it.
Try re-seating the RAM first and also try a different PSU.