Hi, I've read quite a few posts on this forum of people having the same problem but haven't really found a solution for whats going on with me so I figured I'd try posting. I was having a lot of page faults in non paged area error messages for the last week or so on this brand new built system and read somewhere that Norton Antivirus might be the culprit. I was running an older version of the corporate edition and uninstalled it. I also ran memtest (which ran without any errors for over 4 hours) and also ran two instances of prime95 with each using 850 megabytes of ram. I have done this twice and both times the prime95 instances max out the dual core cpus at 100% and the computer works fine for around 12 hours. Both times at around the 12 hour mark of torture testing, the computer restarts with the page fault error in non paged area. I have a 400 Watt antec power supply and temperatures remain constant throughout the test with my CPU not going over 62-64 degrees celsius. I can't seem to go longer than 12 hours without having it mess up and I don't know what could be causing it. I have already swapped out both sticks of 1 GB ram that I have with new ones and the errors continue. Someone at a local computer store here told me that it has to do with my hard drive and the partitions (of which I have 3 on my 250 gb sata drive) rather than the RAM and that if I re-installed winXP and did something to the partitions I would get the error fixed. I'm hesitant to go down that road though because I'd prefer not having to reinstall windows and lose the config I have setup for my computer currently. I'm running WinXP Pro w/ SP2 and all the updates. I uninstalled Norton AV and instead installed McAfee Enterprise edition. The lockups continue. Your help would be greatly appreciated. I don't know if I'm leaving any vital details out but if you could respond I will include them as soon as possible. Thank you for taking the time to read this post---I really appreciate it!