random reboot
Hi Ajax...
I have dealt with numerous random rebooting problems in my job as programmer/tech support for 12 years. I have also read the seemingly endless posts on endless forums on this topic.
From my experience, I have found that most of the time [guessing about 80-90%] the problem is the power supply... or should I say the failing power supply. Most power supply units (PSU) are generic and like most electronic components that are used frequently - they wear out... GRADUALLY.... voltages tend to spike and initiate a system reboot [like a power surge during a bad storm]. With this said, I would recommend you replace the power supply FIRST.
PSUs are generally inexpensive when compared to ram, cpus, cooling systems, mobos, etc... if this does not correct your problem... you have a new power supply and you have eliminated one of the main random reboot variables... a small price to pay when you are looking for a 'bargain' resolution to your problem [doing it yourself].
I have also noticed that some advice is to check your CPU temperature, but I find this distressing because generally... if a cpu has a cooling problem and overheats, the action would not be a reboot, but a system shutdown. Rebooting with a smoking CPU defeats the purpose of the heat-safety programming within the CPU.
I hope this helps... even in some small way.
robert-