回複：It could be caused by virus as well.

Recently, I have repaired a Toshiba laptop for a friend. His problem was that PC ran really hot and hard drive seemed never stop. In about 10 minutes, the PC shut itself down to avoid damage from too much heat. His hard drive was as hot as 60C. I had to place a block of ice below the laptop while trying to clean out virus. I removed about 30+ viruses and the initial problem was solve as well.