I recently built myself a new pc and since day 1 of the complete installation i have experienced some odd stuttering, pc freezing and the occasional sudden restart.
The biggest problem is this stuttering. It comes at random times (every 30 mins to 2 hours - sometimes multiple times within these periods) and is a sudden 1 second of stutter followed by half a second of no stutter and then another 1.5 seconds of stutter. By stuttering i mean audio and performance. Eg. if i am playing any game, say, assassins creed, i will be moving around and all of a sudden both game play and audio start stuttering.
This happens in all applications, even when my PC is idol on the windows desktop (can notice it if moving the mouse around). The stutter is extremely fast in itself.
sometimes bad video or chipset drivers or bios setings can cause it, make sure your chipset and viseo drivers are updated, and if they are, you can always try an older video driver and see if that helps too.
Make sure your bios is on default setup also and see if that helps.
Also, you can try changing the BIOS setting "Is PNP OS Installed?" to "NO" - I found this fixed a similar problem for me.
I believe that hotfix is included in XP SP2
My pc seems to be 100% stable now. I fiddled around with the overclocking features in my bios. Manually set the ram timing to 5-5-5-15 (auto was thinking it was 5-5-5-18) and adjusted some voltage settings as per some suggestions of friends.