Enable Hibernation in Vista
To enable hibernation, click on your Start menu, and type powercfg.exe /hibernate on in your search box. Then press Ctrl+Shift+Enter, which will run the command line you typed in as an administrator.
Diable Hibernation in Vista
To disable hibernation, click on your Start menu, and type powercfg.exe /hibernate off in your search box. Then press Ctrl+Shift+Enter, which will run the command line you typed in as an administrator.
If you have UAC active, it will prompt to approve the elevation of privileges, and you’ll probably see a quick flash of a command line window appearing and then disappearing.