To resolve this:
- Remove any newly installed hardware if any, because your computer may not be compatible with the installed hardware. If installed hardware supports your motherboard then there will be problem with the new hardware settings.
- Remove the RAM and gently rub the copper portion on either side of the RAM (the side where you fix the RAM to the RAM slot on the motherboard) with a soft cloth or pencil eraser and plug it back to the motherboard.
- In the motherboard, checkout the heat sink fan (usually called as processor fan) placed on the processor. The fan should be rotating constantly. If the fan is failed, the processor will get overheated causing your computer to get restarted automatically. There are also chances of your computer getting hanged.
- The other possibility is, the SMPS (Switch Mode Power Supply) otherwise called as power supply may have the problem. Checkout whether the SMPS fan is rotating properly or getting over heated.
- If you still face the same problem then repair your operating system files using your operating system CD/DVD.