First off i'd like to appologise as being 'that guy'. What I mean by that is the random person who floats in demanding answers to his problems and then is never seen again. However, the circumstances mean i'm completely baffled.
To paint a picture... Around 1 year ago, while playing a video game, the computer locked up, I restarted and went along, after about 10 minutes the computer crashed again, only this time there were small visual spots all over. Progressively this got worse and happened quicker, before eventually landing in the BIOS, after 30 seconds it would just show random blocks of nonsense characters, freeze. Being the BIOS I knew this wasn't software, got on the case and determined it was a graphics card problem (that's sensible right?) I could squeeze the computer into safe mode where besides a few problems it seemed to scoot around ok. So clearly a job for Mr. RMA, I sent the card back to EVGA where they sent a replacement.
Same thing happened, corruption blah blah blah. I next did the motherboard, assuming power wasn't getting there or something, no joy, same corruptions over the screen. Finally, what I received in the post today was an RMA'd power supply, stuffed it in, admitedly not too optimistic, only to have the corruptions appear, again.
It seems an apparent heat issue based on that if I cold boot, it takes around 30 seconds to kick in, and with the new motherboard, I can go around the settings, just with stupid white lines everywhere. Whereas if I just restart, the lines appear immediately, all over the logo screen as well.
Other things I've tried, different power leads, different power sockets, obviously removed all unnecessary items (sound cards) tried the computer out of the case, tried a different screen, checked the graphics card temps on original (never went out of the norm) tried 1 stick of ram, cleaned the insides, reseated everything.
Only thing I can think of now is that it's what I originally thought, the graphics card, and i've just ended up with another duff one, but seems a little to coincidental to have one experiencing the same difficulties.
Intel Core 2 Duo E6750
OCZ DDR2 PC2-6400 SLi Ready
ASUS P5Q Pro Turbo (NEW!)
Western Digital 320GB Hard Drive
EVGA 9800GT (NEW!)
OCZ ModXStream 700Watt (NEW!)
Windows XP Home Edition
Well those errors look familiar, I'm having the same issue on my 9800 GX2... I bought it refurbished but it was right from the manufacturer (BFG Tech). The card ran fine for 4 days on Windows XP Pro (32bit), after I installed Windows 7 (64bit) it started to slowly degrade. Unfortunately letting it cool down doesn't solve my problems for any amount of time. Well here's to hoping the replacement card will work better!