Well, I can't think of ANYTHING else to have you try other than to try reginaldperrin idea from a previous post and try a new/different power supply. I would have thought other weird things would have been happening in the last couple of months if it were the power supply though. (possibly even gave up all together) That's all I can think to tell you. (unless you have a bad/flaky motherboard)
My problems were in a similar situation, caused by overheating of the RAM modules. By separating them, the additional airflow has resolved the problem. Turn on (install) the lm_sensors package, which will monitor your RAM and CPU temperatures, assuming your motherboard has the appropriate thermal sensors.
Originally Posted by Dominikl