A little after installing Service Pack 1 for Windows 7 Pro x64, my graphics card had seemed to fail.
My computer randomly crashed for the first time in-game, so I rebooted to find that my screen was now covered in large oddly-colored pixels. Reseating the card and DVI cable fixed the pixel error, but I was still getting crashes in-game.
I installed new gfx drivers (thinking SP1 and my current drivers had issues with each other) via uninstall, driver clean, and new install, but crashes still occurred.
Then, I performed memtest to find 0 errors and finally swapped out the card for my 2nd (which I only had because I had multiple HDDs and the 2nd, which used to be used for SLI, could no longer fit with them together in the mid-tower). Swapping out the cards did relieve me of the crashes that would occur within minutes of starting the game, but I still crash when I've left the computer on for 3-4 days and then start a game.
I clean out the computer once a month and the fans all work, so I don't think it's overheating. I have a 1kW PSU and I bought it anticipating both gfx cards and a 5-year degradation (the power supply calculators online said ~950 Watts with 50% Aging), so I doubt it's a failing PSU.
Can anyone enlighten me as to what other things to try in order to eliminate these errors?
Also, right now I am assuming my 1st gfx card to be "dead," but if it could be something else, please tell me. Dropping $450 is a significant amount.
CPU: Intel Core 2 Extreme QX6800 (Stock: 2.93 GHz OC'd to 3.5 GHz)
Mobo: nforce 680i LT SLI
RAM: 8 GB (4x2 GB) DDR2 800 MHz
GPU: Geforce 8800 Ultras (Only use one, but used to be 2 in SLI)
SPU: Creative X-Fi XtremeGamer
HDD: 3x500 GB, 1x1 TB (all 7200 rpm SATA)
PSU: 1kW Ultra X3
sc2, css, and vindictus, but I play these on medium, so it shouldn't be a problem... the 8800 Ultra is fine specification wise... If I can play sc2 on low with a low-med-end laptop GPU, I can definitely play them with a 4-year old high-end desktop card...