How To Stop PC from rebooting automatically

MY computer has been rebooting itself for seemingly no reason. When it restarts there's usually a message saying it's recovered from a serious error. What's the matter?
Your computer is probably overheating, which usually happens if you’re using a program that demands a lot of processing power — like a game or graphics application.
If your CPU runs at over 60 degrees your computer may shut down automatically to prevent the CPU from burning out. It's possible that the fins on the heat sink under the CPU are covered in dust, restricting airflow and preventing decent cooling. Cleaning the fins may well reduce the CPU temperature.
Try Google to find a lot of free utility that tells you at what temperature your CPU and harddrives are operating.If overheating isn’t the problem, bad memory is probably the culprit. Open the PC case, remove or replace on RAM stick and run your computer for a while.
If your computer doesn’t reboot, you've found the source of your problem.If your problem does recur though, repeat the process for each RAM stick until you find the faulty memory.