Disable Hibernation
Unlike other versions of Windows Hibernation is part and parcel of the shutdown options of Vista. There are no options in Power options to actually disable it. If you don't use it then hibernation will be taking up valuable disk space, therefore it is easier to disable the option and reclaim the disk space allocated to the hiberfil.sys.
To disable hibernation proceed as follows:
1/ Click Start followed by All Programs and then Accessories
2/ on the Accessories menu Right Click on the Command Prompt
3/ from the drop down menu, Click on the Run Administrator option
4/ The Command Prompt window will now open
5/ At the command prompt type: powercfg -H off
To enable hibernation
If, after you have disabled hibernation you wish to re-enable it, proceed as follows:
1/ Click Start followed by All Programs and then Accessories
2/ on the Accessories menu Right Click on the Command Prompt
3/ from the drop down menu, Click on the Run Administrator option
4/ The Command Prompt window will now open
5/ At the command prompt type: powercfg -H on
Disk CleanUp Option
A less complex option for disabling hibernation is to use the Windows Disk Cleaner
1/ Click Start followed by All Programs, Accessories and then System Tools
2/ From the System Tools menu, Click Disk Cleanup
3/ Choose which files to clean up
4/ Next select the Windows Vista drive and press OK
5/ Disk Cleanup will now scan your system
6/ When the Scan is complete the Disk Cleanup for Vista window will open
7/ If it is not already there, Place a Tick in the box next to the Hibernation File Cleaner
8/ Enable or Disable any other file options you want to clean from the available list and then Press the OK button
9/ Hibernation will now be removed
10/ If you need to replace hibernation, follow the instruction in the 'To Enable Hibernation' section above.