I would start by changing out the CMOS battery. Then clean the inside of your computer. Dust restricts the airflow and prevents proper cooling. This in turn can cause overheating and faulty processor fans which can result in unexpected shutdowns, random restarts, booting problems, etc.
- Open your machine, check all the connections and make sure the fans are all operational.
- Remove the CPU's cooling unit and clean the fins on the heat sink that sits under the CPU with a can of compressed air.
- Inspect the thermal compound between the CPU and heat sink as it can deteriorate over time so. You may need to remove it, scrape away the old thermal gel that makes contact with the processor, then apply a very thin coat of fresh thermal gel on the surface and fit the heat sink back in place again.
- Feel the CPU heatsink when it powers down. It should be warm to very warm but not hot.
- Monitor the temperature of your CPU, motherboard, hard disks, voltages, and fan speeds.
See "Cleaning the Interior of your PC
" and "Getting The Grunge Out Of Your PC
".Other Troubleshooting Tools:
Download and run Motherboard Monitor 5
. If Motherboard Monitor's seems to be reporting high temperatures for your CPU check to see what your max CPU temp is from here
You can also use NextSensor
to check temperature and voltage or SpeedFan
to monitor voltages, fan speed, SMART status, and temperatures. SpeedFan can help you investigate the reasons for an unpredictable reboot or for a failing hard disk as well as whether you are likely to experience temperature related issues.
There are suggestions for troubleshooting power supply, video card, CPU, RAM, MB and hard drive here
Since this issue appears to be hardware related, I am moving your topic to the Hardware forum where you can receive further assistance if needed.