my CPU turns off automatically when it gets hot and its fan starts and in 2to3 hrs the fan stops and it starts working. but now light was on on start button on CPU and it stopped and fan started after half hr I turned off start button and the fan stop and when I tried to turn on start button it doesnt turn on but fan on for a second and off automaticly.
You are having heat problems!
Clean internals of computer (CPU)! Pay special attention to all heat sinks and fans! Reset BIOS to defaults, remove motherboard battery for min and put back in! Try again!