Then that wouldn't be the problem... Hmm
So tell me what it does, you turn it on, it boots up into windows, when you play a game does the card stop working and doesnt work again til you reboot?
what Nvidia driver are you using?
I know with the newest driver my card will stop working but fix itself within a second or two but it only does it when I overclock my card too much.
It sounds like you need to just update windows and your Nvidia driver, he other car works and your card works on another computer, the problem is your computer. I would say it wont support your card til it gets an update, I'm running Win 7 Ultimate 64bit and it booted the card the first time so i could update.
Or maybe do you atleast have the disc that came with the card?
So it usually hangs as soon as I boot into windows. I'm using the latest driver 296.10 I think it is and win 7 home x64. I have all most recent windows updated too