Ok i searched and no ones problem is quite like this - i have a Mirror doored dual 1.25ghz PowerPc mac with like 1.5gb ram and 500gb hd and just a normal apple studio display 15'' here's what it does - randomely it will turn the screen off for a few seconds then back on then off then on then...you get the idea. but here's the trick - the power indicator on the the computer obove the superdrive turns off too and for a second it looks like the computers totally off but its not your cursor stays where its at on the screen and its fine ...for about a minute then off for a few seconds. any ideas? sorry for the lame explanation it just did this last night and i hope theres nothing too wrong cuz i have a LOT of stuff on this computer i don't want to lose.