Try the Memtest 86+ I linked you to and see if that brings on the problem. If it doesn't I would look at your HDD having an issue. Alos make sure your bios is up to date. you also can try resetting your CMOS.
It is the round silver thing the size of a 50 cent coin. You just pop it out wait about 3 min. Then put it back in. Or there is place on your MOBO that you can short it out but you will have to get your hand book to find it.
Then let us know what you have come up with.