I've been having some issues with system freezing during UT3 play and freeze ups when I run nTune stability Test. The Epic games forum says there are driver issues and game issues when running UT3. I downloaded 169.28 Beta driver in order to supposibly run UT3 without issues. That didn't work out to well. Anyways I went to nVidia and got the 169.21 WHQL driver; figure i'm better off with a logo'd driver. My system settings are  nVidia 8800GTOC is running at 120degrees with the fan speed set at 60%. So heat shouldn't be an issue. Core clock ROP 600mhz, shader clock 1500mhz and memory clock 1000mhz.  Monitor res. is 1024x768. Why would my system lockup when I run nTune stability test? Screen gets pixely and freezes then it needs a hard reboot. I even went to microsoft and made sure I was up to date on everything. One more strange thing I found was that dxdiag says my OS is XP professional 5.1 build 2600 when i know its XP media edition sp2. I use RivaTuner for my card settings. When I look at my hardware monitoring it says my shader clock is 1512mhz and there is an ! in yellow on the adjustment. Seems like a confusing post but all I want to know is if anyone can make sense of how my system can be unstable. Thank you for any help.