Hey, I have a question about this build. My girlfriend has a computer with an ASRock N68-S UCC motherboard. As of right now, she has an Nvidia GeForce 9500 GT in it and I'm trying to put a Galaxy 250 GTS in it. The 250 GTS is used, but is known to be good. I've tested it on my computer and it works flawlessly. However, when I hook it up to her computer (plug into PCIe slot and plug PCIe cable from PSU into it), the computer starts up and you hear the Windows logon sound but the monitor has no display. I've tried 2 PSU's on her computer and both give same results. Her old graphics card works fine so I know the slot works. The PCIe cable from PSU has to be good since the likely hood of 2 PSU's giving exact same problem are slim. I was wondering if there's a compatibility issue between that graphics card and her mobo. I can't find anything on it. Any ideas?
EDIT: the specs on the PSU's tested are a 500watt and a 680watt