why would scrn saver or sleep not start?

[BilltheCat]

wife says she was putting laundry away and saw the imac was lit up on the desktop. no scrn saver and not asleep.

It is set with a screen saver after 15 minutes of no activity and goes to sleep in one hour. But it isnt doing it now.( I am at work now. have been since 4pm)

any clues as to what could be interferring?

Thanks!

 

[mad jew]

What apps are running? What do you have plugged into the machine? If you've reset the PRAM recently, these settings may have been returned to their defaults so double check they're still as you want them in System Preferences.