a friend gave me a laptop and i was cleaning it up when it started randomly shutting off. first i was doing a cleanup and it shut down during a malwarebytes scan. then i rebooted and it finished. then when installing avast right when it started coping files it would shut off. when it shuts off its like your pulling the power out so there's no errors in the log or minidumps. i tested the hard drive and its good. i ran memtest86 and after about 6% tested it shut off. i tried each stick individually and in each slot and it shut off on every one of them. then i tested the ram in another laptop and they passed. i left the laptop on all night long and it was still on when i got up. i'm stumped. all i can think of is blaming it on a bad memory controller, but i think thats just an excuse that sounds good.