Macbook Sleep Problems

Okay, this is weird. When I shut my machbook, it will not go to sleep. It will stay quiet, but the "wake up from sleep" mechanical noise plays after seconds and the bottom of the computer gets very warm. When i put it on sleep from the menu, it will wake itself up within seconds, and the screen will light up. Now, the white light on the front stays bright white when it is shut. It makes no difference if it is on the power adaptor or not. It also doesnt matter if all of the programs are off or not. I have fiddled with the energy saver settings and it is having no effect. Thanks for all of your help!

AJB

do you have any usb devices plugged into it? they can wake it up.

nope. no USB accessories. i have even turned off my airport and it wont go to sleep, just will stay awake.

Have you checked System Preferences->Energy Saver for checked items?

What about a bluetooth mouse or keyboard? There is an option in the preferences to allow bluetooth to wake the computer (not at the mac right now, so can't be more specific). Could that be the problem -- maybe moving the mouse to get it out of the way??