Windows XP system suddenly reboots
I've been having PC issues and hope someone might have some ideas. For what it's worth I have an Intel Duo Core E6750 (2.66 G) CPU, 2 GB DDR 2 memory and a 500 GB WEstern Digital SATA 2 hard drive. The motherboard is an MSI "P35/G33 Neo Series Express Chipset". No overclocking of the CPU.
In the last couple weeks I've started having issues with my computer rebooting randomly. It can be once a day (I leave it on almost all the time) or several times a day. There seems to be nothing in common with when this happens. Sometimes I may be using the Internet, sometimes typing a document, etc.
I'm using Windows XP, Service Pack 3 on a PC built in 2007. I have looked in the Event Log but find no entries that indicate an error. When the reboots occur the screen simply goes black. Checking the log after each of these shows two events, 6005 and 6009 at the time of the reboot. The previous events are often minutes before the reboot and are usually 7035 and 7036, which seem to be fairly common based on the number of them in my log. I've told Windows not to automatically reboot on an error but this seems to have no effect as there is no message or anything - just the black screen and then rebooting. On a couple of occasions it has frozen totally for a few seconds before blacking out but nothing appeared in the log from this either.
I have used both AVG and ewido to neaten up my system. These seemed to find only smaller things like tracking cookies, etc. I also used Registry Mechanic to clean up the registry.
I've downloaded some freeware stuff to check out some hardware. "HDD Health" tells me my hard drive has 100% health. I also ran the disk checking program included in Windows and after three hours it found no errors.
I did several passes with the memory test program (Windows Memory Diagnostic) that I got from the Microsoft website and it found no issues with my 2 GB of memory.
I'm using "Speedfan" to monitor temperatures, fan speed and voltages. My CPU temperature is around 55 C but was higher than that (around 62 C) when I left the case off a couple of days ago to clean up in there. There seems to be no capacitors on the board that are bubbled out, or whatever that phenomenon is called. Everything looks normal.
Last night I left the machine running in Safe Mode overnight and it didn't reboot. I had to use it today so after 11 hours of no problems with Safe Mode I restarted into full blown Windows and had two reboots in two hours.
I'm left wondering if maybe I should replace the power supply. The voltages monitored by the "Speedfan" program seem to be very consistent (eg. 12.3-12.4 V) over the several days I've ran this program. There are no significant deviations across this period in any of the readings although fan speed may vary by up to 200 rpm (normal speed is about 2200 rpm).
The only other things I can think of are to format or attempt to repair Windows. This is not something I really want to do and am hoping someone here might have some better ideas? I'm running out of things to try.
I haven't changed anything in the past while. The system hasn't been moved and I've installed no new hardware. There are no errors reported in "Device Manager". The one curiosity I noted is that my "System Restore" points don't work. I did install several Windows Updates and I read somewhere that could affect the ability of System Restore (not sure) so restoring to an earlier date is not an option for me.
Everything sounds normal and all the fans are working.
Any help or suggestions would be greatly appreciated.