A friend-of-mine's computer from 2005 was acting like sort of like that a few months ago. Turned out the paste dried up under CPU heatsink. So...maybe some new thermal paste couldn't hurt. Just for good measure.
We'll murder them all, amid laughter and merriment...except for the few we take home to experiment!
"I cant see S***! --YOU GO TO HELL!" --Tourettes guy