Well, this about the tenth time I have tried to post on this board. My PC keeps rebooting and I have to keep starting all over again. This is not a new problem, it just has gotten a lot worse in the last few days. I have tried everything to figure out what is causing the problem. There seems to be no consistency to this problem. It happens randomly. I have tired to compile a detailed list of errors, specs and repair procedures I have tried, so that we can forgo me trying things I have already tried multiple times. Before we get started you need to know what my system is so I have made a detailed report of my system available at this address http://members.tripod.com/defaultsite2/my_system.htm What is my computer doing? The problem manifest itself in several ways. Sometimes the computer will suddenly shutoff and reboot as if you had pulled the power cord out of the wall and plugged it back in or hit a hard reset button. Sometimes it will suddenly begin the shutdown and restart process. Sometimes it will turn itself on by itself. Sometimes it will start up and run fine for hours and then suddenly shut off and restart. Other time it will run fine for just a few minutes before it does it. Sometimes it will will boot up, shut off and restart multiple time at different places in the boot process. What errors is it reporting? I have checked the Event Viewer many times and it has never reported a single error about this problem. Each time I reboot the Windows error reporting tool comes up and I have sent a report off every time. After sending the report a web page will open and tell me what caused the problem. There have been three types of problems that this page has reported. 1. A device driver caused a "Stop Error". 2. A Memory Write Error. 3. A Hardware Failure Error. What have I tried? 1. Updated all drivers (GPU, Motherboard, Bios etc.). 2. Replaced master hard drive and installed fresh copy of Windows XP. 3. Replaced CMOS (Motherboard) Battery. 4. Unplugged power button connector from motherboard to test to see if there was a short in the button or wires. 5. Ran multiple pass memory test (Windiag.iso boot level memory scanner). 6. Performed thorough cleaning of tower and all components. 7. Check motherboard and CPU temperatures. 8. Performed advanced Registry scans with Iolo System Mechanics and Norton System Works. 9. Turned off Window Automatic reboot. My system has suddenly rebooted several times since this and has only shown me a BSOD once. See this screen at this address: http://members.tripod.com/defaultsite2/BSOD.jpg I might have done other things but I can't remember them all. Here is the thing. After doing all this, my system is running better and faster then it was when it was brand new, all except for this rebooting problem. I am at my wits end as to what is causing it. About the only thing left to replace is the motherboard and CPU. I am about ready to do that, but I just hate to throw away a good system if I don't have to. So what to you think guys? Have any ideas for me? Thanks for the help.