Windows Sleep Problem

[the DRIZZLE]

I have a desktop PC running windows 7x64. It will not go to sleep on the inactivity timer no matter what I set it to. What's strange is that it will turn off the monitor on the timer. Is there a way that I can figure out which process is preventing it from going to sleep?

edit: It will go to sleep correctly if I manually put it to sleep.

 

[the DRIZZLE]

I solved it. I have a Adobe PDF converter as one of my printers and it had jobs stuck in the queue from months ago. Windows won't sleep with jobs in the printer queue.