Strange power supply issue

First all, I'll start out asking if I have 2 modular PSUs( in my case a seasonic and an OCZ) and if I try to use a cable from the Seasonic (not the main cable that goes to the wall, but a modular one) and use it in the OCZ, will it work? If this answer is no then I already have my answer, else I'll try to further explain my problem below.

I had a 650W Gold seasonic PSU that died about 2 weeks ago after just 1.5 month of use. A buddy of mine has a 600W OCZ PSU that he got from his work that doesn't have any cables associated with it. The video card that was in his computer was a workstation card so it did not require a 6 pin connection for power. So as I said I have been trying to use a 6 pin to 6 pin from my extra Seasonic cables but I get the following problem. When just the power to processor and the motherboard are plugged in, the bios will post but throw and error message that im assuming to be no video card detected. When I then plug in a video card (after unplugging and whatnot) the processor fan will kick, but not continue to spin and the bios does not try to boot. This has happened on both my machine and his machine, and I have no idea why. I believe that his PSU is actually healthy (maybe its not) and I know my PSU is dead as it doesnt even give power to the motherboard. Unfortunately I don't have another PSU to try and test this on.

Anyone have any ideas whats going on? I have racked my brain thinking what could be the culprit and I can only see either the PSU is bad or the cables aren't compatible.

Thank you for your time.

My spec for those who want them but I do not believe them to matter in this situation:

i5 2.6
660ti MSI
2 4GB corsair Vengeance RAM sticks
An SSD and HDD