Can't exit screen saver!

Question

My sister's iMac G5 goes into a screen saver or the display shuts off, or it goes to sleep and she/we can't exit the screen saver or black screen. The screen saver is always active--doing it's thing. It's not like a crash.
We move the mouse, press keys, etc., and the only solution is to hold the power button down until the computer shuts off and then press it again to start up the computer.
She has lost many a document this way.
Wake from sleep issues have plagued every version of Mac OS X since its inception. Apple has been trying to fix this problem, but it plagues every version of OS X.
I've run virtually every utility to try and prevent the problem but without success.
Does anyone have any tips?

Answer 1

Try resetting the computer's PRAM by rebooting the computer and holding down the "options-command-P-R" keys all at once until the computer resets again and makes a second set of boot chimes. Then release the keys and allow it to boot normally.
Additionally, you might try creating a new user account to see if that also crashes when screensavers are activated. If things are fine then you might have to migrate her account to a new one, or at least be able to troubleshoot her current account.