Windows 7: Computer not entering sleep mode

Just recently my computer has not been entering sleep mode. Nothing changed from last week and now it doesn't go. I can select sleep from the start up menu but it instantly turns back on. I went into device manager and deselected all usb and my wireless mouse and keyboard from waking the computer. Still won't sleep but now can enter sleep mode from the start menu and will stay asleep. However won't enter sleep by inactivity. If I unplug the usb receiver the computer will enter sleep like it use to. What going on? Even changed the batteries, because this happened a year ago and it was becuase they were dying, but didn't help this time.

Thanks

Does the machine still go to sleep before it turns back on? If so, what output do you get if you run the command powercfg -lastwake from an elevated cmd prompt?

With my wireless eyboard and mouse not set as a wake function, the computer won't go to sleep at all with inactivity, but will go to sleep if i select sleep from the start menu. Once I do that the computer will stay asleep till I wake it by hitting the power button. The "lastwake" in command prompt is of course "power button". But I want it to go to sleep like is use to by inactivity for 10 mins. If I unplug the usb receiver for the keyboard and mouse the computer will enter sleep mode after 10 mins. So I know it is conflict with the wireless keyboard or mouse. All ready uninstalled the drivers and software and reinstalled. Checked for updates as well.

Well, it could be the receiver picking up interference if it's not bluetooth. I would doubt it's a driver issue, as you mention it sleeps just fine if you put it to sleep manually.

you could try this command from an elevated command prompt to see if any devices can wake the system.

Powercfg -devicequery wake_armed