Windows 7: Win7 and geforce 250... games make the comp freeze

i have a geforce galaxy gts 250 512mb and in linux/xp 32bit it loads games fine, but in Windows 7 64bit (havent tried 32bit Windows 7)my whole computer just turns black when i try to play. no sound, no response from the normal ctl alt dlt, not even a numlock response. takes a manual restart to get going again. i have tried the drivers that came with the cd, ones that galaxy officially supports, and the nvidia official drivers. Could it be this card isnt supported very well in 64bit Windows 7 yet? Or could I possibly need a new psu? Thanks to anyone with ideas...

e6300 2.8 wolfdale
4gb 800 ram
asrock p43de
galaxy geforce gts 250 512mb
160gb seagate 7200rmp sataII
505 watt psu

Would need to know the PSU maker and model # to check the amps on the 12v rail but pending on whatever else is drawing from it a 505W should be enough but it's always the amps that count in the end. Fabe

nspire nsp-405v2.0f12 405w atx2.0 120mm fan psu

after a quick google search i cant find much specs yet... had my psu replaced a year a go or so and had to downgrade from a nice 605w psu

edit:
Voltage Output : +5V = 28A , +12V1 = 10A, +12V2 = 15A, 3.3W = 18A, 5Vsb = 2A

Based on the requirements on your card of a minimum of a 450W power supply with 24 amps on the 12v rail http://www.galaxytechus.com/usa/productview.aspx?id=76 That your combined Amprage with both rails is only 25 amps. So your a bit under powered for that card. Along with everything else that draws off it. I would reccomend this one of course since I have it and run a gtx260 supperclocked. Also if you check my specs you'll see what all it powers. http://www.newegg.com/Product/Produc...82E16817341023 Others will have different suggestions but IMO your power supply is the heart and soul of your system so never skimp on it. Heres a thread on PSU's that explains a lot post #8 http://www.sevenforums.com/vip/47352...tml#post445442 Hope this will help Fabe

What games are you trying to play?

prototype, guild wars, ff11 sometimes works for a few min then freezes, even d2 freezes...
i have tried all the compat modes with each one. they start in xp for a few min then crash. in 7 it freezes as soon as it goes full screen.

i have ordered a new 600w psu btw. supposed to be for sli so it should be good for one card.
ill get specs after work. hopefully that helps. any other ideas in the mean time?