At 11:50 AM 4/30/2008, you wrote:
OK Guru's.........here is the problemGot box running XP Pro; and it reboots several times a day on its own (just sitting there or not).
Assuming you are not over clocking or running hot, then spontaneous reboots are almost always caused by bad RAM. You write that you have replaced the system RAM, but not the video RAM. I would swap out the video card with any other video card to see if the problem goes away. If that isn't it, suspect the PS.