Mac OS 10.1 sleep problem

My AGP Graphics Macintosh G4 has suddenly started refusing to go to sleep on command, or rather, it goes to sleep for an instant and then immediately wakes up again.
Alwyn wrote on :

My AGP Graphics Macintosh G4 has suddenly started refusing to go to sleep on command, or rather, it goes to sleep for an instant and then immediately wakes up again. The only change I can recall making recently is connecting a USB printer to it, but the machine won't sleep even if the printer isn't connected.

Has anybody seen anything similar?

Alwyn