HOW TO ENABLE OR DISABLE THE HIBERNATE OPTION IN WINDOW VISTA

Hibernation is made unavailable when you set the value of the Hibernate after setting to Never by using the Power Options item in Control Panel. To
make hibernation unavailable, follow these steps:

To make hibernation available, follow these steps:
1.
Click Start, and then type cmd in the Start Search box.
2.
In the search results list, right-click Command Prompt, and then click Run as Administrator.
3.
When you are prompted by User Account Control, click Continue.
4.
At the command prompt, type powercfg.exe /hibernate on, and then press ENTER. .(You must be at the c:\> by using the cd\)
5.
Type exit and then press ENTER to close the Command Prompt window. .(and restart the pc)