If you don't use hibernation on your pc it is fairly easy to disable, and at the same time free up a few gigs of disk space.  My computer is currently using 5.6 gigs of disk space for a Windows feature I don't use.

When you turn off your computer using hibernate, the operating system needs to store all your current running program states onto hard disk so that programs can resume where they left off when you power up your PC again. To achieve this, the OS need to save all the information into a file called hiberfil.sys. Windows OS (7, vista, XP) usually stores this as a hidden file under your C directory or your main OS partition.

So if you never use hibernate, than its time for you to get your hard drive space back.

[Note: Hibernate mode is not sleep mode. When hibernating your computer completely shuts down, however, under sleep mode your PC is not completely shut down; it still consumes a small amount of power.]

The best way to delete hiberfil.sys or disable hibernate:

   * Go to Start menu, type “cmd” open up command prompt
   * Type “powercfg.exe -h off” [make sure you are an Administrator]
   * ENTER
   * Type “exit”
   * ENTER


Taken from windows7hacker.com

Is it same on xp?

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Haven't checked.  Couldn't hurt anything to try it though.

How much space did it open up for you tet?

GOA.Luke*BK*

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I would get an additional 3gb

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with vista i gained 3.1gb.  thanks tet, awesome find!

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I think it's dynamic based on what you have been running and for how long.  Not sure on that either though.  But mine was 5.6 gigs worth.

Says I don't have permission...does it have to have you as adminstrator next to your name on the command prompt screen?

When I go into user accouts, it shows me as the admin, but not on the promp screen.  

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You can check how much you'll free when you go to energy saving in your screensaver options window. There's a tab called hibernation and it tells you how much space it take to hibernate.

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