Not sure what is wrong with my PC!

[roxkyp]

Hi!
Since a couple of weeks back, I can't get any connection from my 7970 in slot 1, so I switched to slot 2. In slot 2, I can get a display, but as soon as I run any program or game that involves the GPU, the computer crashes. Weird. So I tried to run with an AMD 5450, same problem there. Bought a new motherboard since I thought that was the problem, but it still persists (same model but another motherboard, Asrock z77 PRO4-M). I have no idea what the problem is, and I can't get my head straight until I fix this, so any help at all is appreciated. My setup is: AMD Radeon 7970, i5 3570K, 16GB XMS3 Corsair, OCZ ZT 750W, Asrock PRO4-M and finally Windows 8.1.
As I stated before, I'm completely stuck and would appreciate any help at all, thank you!

 

[roxkyp]

Thanks for all replies! Right now I don't have access to another CPU or computer, however I think I have an older PSU, but thinks it's only 350W so that won't work either with 7970. I'm not getting any signal at all in port 1, however the monitor detects something is going on. Bios is updated to latest, have always been updated to the latest versions!
Once again, thank you for any help!

 

[roxkyp]

You say you get the problem with the 5450 too? So you could try the 350W PSU with the 5450 GPU to see if you still get the problem. That GPU gets all its power just from the PCI-e slot so the PSU should be enough.

Haven't thought about that actually, will try directly as I get back! And I'll mention it again, I'm thankful for everything!