Sorry this ended up being so long. If you want a quick digest, here you go: My system was rock solid stable until I started overclocking the video card a little. It seems that ever since I installed ATI Tool that I get visual artifacts and crashes after about 5 minutes. I've tried it all, but it seems like maybe my card is damaged. Is that possible? How can I know for sure? What should I do next? Ok, now here is the full on detailed post!... I have a new EVGA 8800GTS. I built a new PC for it and freshly installed Windows XP SP1. It was working great. I have mildly overclocked my CPU, FSB, and RAM and have run benchmarks like 3DMark06, 05, 03, Orthos, and memtest86 to verify stability. Everything was stable. The last thing for my install to be complete was to overclock the video card. Using nTune, if I click the "find optimal" button a blue or grey screen is shown and the PC freezes. So instead, I overclocked slowly with the nTune sliders. I read most people find a stable overclock at 600/900, so I stopped when I got there. Ran a little 3DMark06 and it seems to be stable. Googling, everyone has the same problem with the "find optimal" button. Everyone says they used ATI Tool to do their 8800GTS overclock and that it works great. I've used it before and its much easier to see if you are getting artifacts than by running 3dMark06. I installed ATI Tool and ran it. I clicked "show 3d view" and a blank 3d view window appeared and the computer froze. I rebooted, ran ATI Tool, this time I clicked "find max memory". The 3d view and the fuzzy block was shown and it slowly overclocked the memory. At 875 the computer froze. I rebooted, ran ATI Tool, this time I clicked "find max core". It slowly overclocked the core. At 526 the computer froze. At this point I am done with ATI Tool. I uninstalled it and the system was still unstable. About 5 minutes after I boot and I'm just browsing the web, I start getting visual errors. A few times the mouse cursor disappeared and was replaced with garbage. Sometimes parts of various windows are not drawn. Sometimes the screen freezes and becomes responsive again after 10-15 seconds. Usually though when it freezes it never comes back. Sometimes if I wait long enough after a freeze I get a BSOD complaining about the "nv4_disp" driver. I clocked the GPU back to stock with nTune, still crashes. I even under clocked it slightly. Still crashes. I underclocked the CPU, FSB, and RAM below stock to take them out of the equation. Still crashes. Finally I uninstalled all the nVidia drivers, booted into safe mode, ran driver cleaner, reinstalled the nVidia drivers, rebooted, and the system is still unstable. Desperate, I tried installing ATI Tool again, but it crashes the whole system still. I did notice one of the times I clicked "show 3d view" that is said something about DirectX not being available. I reinstalled DirectX 9.0c, but the PC is still unstable. This whole time the GPU temp is in the 50s and low 60s, so it isn't overheating. Most people say their card runs in the 80s under load, but I never saw mine get that high. I have very good air flow through my case. What do I do now? It kills me that I didn't make a DVD backup before trying ATI Tool. It seems like everything was doing great until I installed ATI Tool. Now it seems nothing I do gets my system back to a stable state. Any ideas? Do you think the card is burnt up? I really don't think I pushed it very hard. Did I ruin any warranty by overclocking? Should I RMA the card? Are there any other diagnostic steps I can take first? Here are my system specs... Intel Core 2 Duo E6600 processor Scythe Ninja Plus (rev B) heatsink eVGA 122-CK-NF68-AR nForce 680i motherboard w/ P23 bios (412x8=3.3ghz) Corsair Dominator 2x1gb DDR2 1066 (PC2 8500) ram (1238mhz) Corsair CMXAF1 ram fans eVGA nVidia GeForce 8800GTS video card AuzenTech HDA XPlosion 7.1 DTS encoding sound card 74gb Raptor HDD Antec NEO HE 550w PSU Antec P180 case Pioneer slot DVD drive Here are some pics of the system.