Hi all, I am copying my post from another forum in the hopes that someone on this forum can take a look to see if this is a Vista issue. ******* I've been reading this forum and Nvidia's official forum for help on my issue. I am pretty much at wits end after searching for a solution online and finally calling tech support at EVGA and getting nowhere. My specs are: CPU: Q6600 RAM: 4 GB (2x2 Patriot Memory) PSU: 750W Silverstone (SST ST75ZF) Mobo: Asus P5E GPU: EVGA 8800GTX 758 MB Monitor: 3007WFP-HC Dell 30 inch Heatsink: Zalman CNPS9500 3 Case fans Vista Ultimate 64 bit SP1 Everything is stock speed, no changes to voltages, etc. My issue is that I started getting TDR errors (Nvidia Official TDR Response) when playing Bioshock and Assassin's Creed. To try and fix the problem, I installed the 175.16 driver set from Nvidia. I did not uninstall my previous drivers, I just installed 175.16 on top of my previous drivers. Everything seemed to run fine for a week--no TDR issues, games ran smoothly. Then a few days ago I was playing COD 4 when the game froze and I had to do a hard reset (this had never happened before as COD 4 was a very agreeable game). Ever since then I get TDR errors whenever I play any game. This wouldn't be too big a deal, but now the problem has migrated so that sometimes when I am in Vista I get display issues where the system just freezes up and the current image becomes pixelated even when I am not playing a game! To rule out other problems, I ran Prime95 to stress test my CPU, Memtest86 to check my memory, and CoreTemp to insure no overheating. I have the latest bios for my mobo, I updated my chipset and so far no issues with any of my HW components... So I decided to uninstall my Nvidia drivers in safe mode, ran Driver Sweeper in safe mode, until I confirmed that no traces of Nvidia remained on the system. I tried reinstalling 175.16, 169.44, and 169.25 all with no success. The only thing that worked to allow me to get into Vista normal mode without freezing up is going to a restore point where I know I was stable and then uninstalling the drivers with the method above and installing 169.44. However, I don't think my system is fixed because I just got a TDR (nvlddmkm.sys stopped responding) while surfing the net. The only good news is that my system didn't freeze. I don't want to play any games as I don't want to have to go through the pain in the a** problem of having to reinstall all of the drivers if the game crashes the system. Does anyone have any suggestions? Did I miss anything? I am tempted to RMA my 8800 GTX, but I am not sure if that will solve anything. Input please--I am literally begging for a fresh look at this! Thanks, Dan