If it's a desktop "hibernate" is useless. If you want to, go to the power settings in "control panel-screensavers" and click on the "power schemes".
Try choosing a different power scheme until you get one which allows "hibernate".
I just got Verizon DSL. Now Hibernate no longer works. Anyone else had experience with this? Could it be caused by some background app added by 'Express Installation', or could it be LACK of some app NOT installed because I did NOT choose 'Manual Installation'? (Verizon have not been at all helpful about this question.)