Regardless of my energy saver preferences, my iMac will not sleep. This is true even when no processes are running. This first started when I used an application called Psyncx to create automated backups to an external hard drive. In order for the backups to run the computer can not be asleep, so I set the schedule in energy preferences to wake/start up the computer just before the backups are to start, early Sunday morning.
When I noticed the computer no longer went to sleep I tried deleting the backups and turning off the wake/start up schedule. Neither has helped, and my iMac still won't sleep. It does sleep the screen.

Am I doomed?
Please help. Please tell me I don't have to borrow my sister's iBook to re-install the OS.