Graphics Card not working and...

[Krezee]

Hello,

I have a 3-4 years old system. 2 days ago I switched my computer off for the night, next morning when I was attempting to switch it on the weird things began to happen.

First of all the graphics card was no longer detected (no signal to the monitors even during boot process) although fans were spinning and it was heating up a bit. Also from time to time when I switch the PC on, it starts for 2 seconds, turns off, and starts back again without any further problems (GPU still not detected). Things I've tried so far:
 

• Clearing CMOS
• Testing GPU in another PC (works)
• Trying different video inputs and outputs, different cables too.
• Unplugging everything from the PSU except mobo and GPU (same results)
• Formatting hard drive.

Nothing seems to really work, every time my monitors go to sleep mode and dont detect the graphics card. However when I connect a monitor to mobo with VGA, pc works just fine, except when the graphics card is there, 50% of the time it does the turn off, turn back on thing.

I am going to test another PSU later today but if it isn't PSU issue I am out of ideas.

Specs:

• Asus M4N68T-M LE mobo
• GeForce GTX460 1GB GDDR5
• 4gb ddr3 ram
• AMD Athlon II X4 3.0GHz stock heatsink
• Seagate 500gb HDD
• High Power 750W Modular PSU
• Windows 7 Ultimate x64 

Everything running stock, never overclocked.
Please help and sorry for my poor english.

[MellowCream]

Yeah, sounds like a PSU problem.

[Krezee]

Yeah, sounds like a PSU problem.

 

Thank you for your reply. PSU was the first thing I've suspected after finding out that GPU works in another PC. I know that 750W is even too much for my system and the new PSU i will be testing is 550W and I'd just like to make sure if thats enough?

I will update you after testing it but just in advance I want to ask if this problem can be related to the motherboard in any way and if yes, what might be the problem with it?

[Krezee]

Ok so I ran few different tests and this is what I've found out.

 

Test #1

Using 620W power supply, other componens same as listed above.

Result: GPU still doest work (PC turns on for 6-7 seconds, (no beep sound) turns off for 2-3 seconds and then back again, beeps, boots up to windows, GPU still doesnt work.)

 

Test #2

800W corsair PSU.

Result: Same as #1.

 

Test #3

I took my mobo (with ram and cpu in it) and gpu to my friend. These are specs for first test (in bold is whats different from my specs listed in first post)

 

• Asus M4N68T-M LE mobo
• GeForce GTX560Ti 2Gb GDDR5
• 4gb ddr3 ram
• AMD Athlon II X4 3.0GHz stock heatsink
• Seagate 500gb HDD (used his HDD)
• Corsair 800W PSU
• Windows 7 Home Premium x64

Result: Work just fine, no problems at all.

 

Test #4

• Asus M4N68T-M LE mobo
• GeForce GTX460 1GB GDDR5
• 4gb ddr3 ram
• AMD Athlon II X4 3.0GHz stock heatsink
• Seagate 500gb HDD (used his HDD)
• Corsair 800W PSU
• Windows 7 Home Premium x64

Result: Same as #1, doesn't work.

 

Test #5 EDIT: Ram and cpu used here were actually different

 

• MSI mobo (don't know exact model)
• GeForce GTX460 1GB GDDR5
• 4gb ddr3 ram 8gb ddr3 ram
• AMD Athlon II X4 3.0GHz stock heatsink AMD FX-4100 Quad-Core Processor 3.60GHz
• Seagate 500gb HDD (used his HDD)
• Corsair 800W PSU
• Windows 7 Home Premium x64

Result: Works fine.

 

Test #6

• Asus M4N68T-M LE mobo
• GeForce GTX560Ti 2GB GDDR5
• 4gb ddr3 ram
• AMD Athlon II X4 3.0GHz stock heatsink
• Seagate 500gb HDD
• High Power 750W Modular PSU
• Windows 7 Ultimate x64

Result: Works fine.

 

This is really weird, the only configuration in which the GPU doesnt work is when I use my GeForce GTX460 1GB GDDR5 and my Asus M4N68T-M LE mobo. Both work perfect independently, but when together, the GPU doesn't work (fans spinning but no display or signal).

 

Any ideas?