hey all lately my computer has been freezing during screensaver. not at the beginning necessarily, at random times when the screensaver is on. i never see it occur, i always go back to my computer and the computer is totally frozen and the only thing to do is hold down the power button to shut it down and restart. any ideas on what that could be? (possibly related: a couple of weeks ago at night the computer randomly shut down twice while sleeping) thanks!