Home systems often are not for 24x7 usage.
Possible effects are:
1. AC power dip. Hint: supersizing a power supply really helps here. That oversized PSU will last more milliseconds if the AC drops out.
2. Alpha particle upsets a memory location or registry in the CPU. Light reading about SEU and more with this Google -> http://www.google.com/search?&q=alpha+particle+upset+computer
3. In short, you may never know. This OS is not going to reveal all possible upsets. Did you look in the Event Viewer for a clue?
4. Heat. Simply and not so simple is that many look at the CPU temperature but don't know what else can be running warm. If the upset happens often enough, I remove the case cover and ask "Better, same or worse?"
Bob
About the system rebooting for no apparent reason. Mine did that today while idle. Yesterday I ran Norton A/V, AdAware, SpyBot, CWShredder with their latest definitions and upgrades and found no virus or parasites. I repeated it today after the rebooting and found also nothing. My system is protected by Zone Alarm.
I have no problem so far with my power unit which I think is 400W.
So what's wrong?

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