My computer keeps Re - Starting without telling me! Help?

You maybe over heating remove cover & clean the inside with a none static soft brush clear all airvents then try it again if that doesnt work Re-format your PC & set it back to factory set This will delete all that is on the PC & effectively rest-it as a new one as you first bought it just make shore you back-up doents to a separate hard drive first. re-formatting should work if don't bye a new one