How to Turn Off Hibernation in Windows Vista
If your PC is running low on memory, you should think about whether you want to turn off the hibernation function in Windows Vista. Hibernation is a modified version of sleep mode that preserves your workspace and all your open files, but doesn’t consume battery life while hibernating. Sounds good right?
The problem with hibernation is that Vista reserves a very large place on your hard drive for the hibernation file. Whenever your system goes into hibernation, it creates a copy of the PC’s entire memory file in this file. Thus, the hiberfil.sys is as big as your system memory. If you have a 2GB machine, that’s a sizable chunk.
If you’re using a desktop PC that’s never allowed to sleep (check the power settings by clicking Start, immediately typing power, and pressing Enter) or your computer is low on disk space, you can turn off hibernation mode to delete the hibernation file and free up some space.
Choose Start→All Programs→Accessories→System Tools→Disk Cleanup.
The program scans your disk and tells you how much space you can save by deleting specific kinds of files.
Select the hibernation box along with any other file types you want to delete.
Checking this box turns off hibernation and deletes hiberfil.sys from your hard drive.
Vista will delete the hiberfil.sys, which not only opens up more space but also deactivates the hibernation feature.