ok, this is strange. my 17 inch iMac (first gen core2 duo) shuts itself down for no reason, the power saver has it set to NEVER put the system to sleep, however this is just shutting down, not sleeping. also, my screensaver activates even though i have it set not to. this doesnt happen if there is user imput, but only if the system sits still... what gives? i am going out of my mind here.