I had the same issue, turned out to be a bad motherboard, take it too a pc repair shop to verify, most won't charge you anything and it can be done in about 10 minutes or less, do that before spending money on a new board first. You can also look at the capacitors over by your cpu, if the tops are bubbled then thats your issue.
If it is your board, you can get a new board with the same chipset you won't have any problems, if not then you will need to reinstall the OS.