Hibernate Mode saves your current session to the hard drive and turns off your computer, allowing you to return to that session when you come out of Hibernate. If you don’t use Hibernate mode on your Windows 7 computer, you can free up some disk space by disabling it.
Hibernate stores the current session in hberfil.sys, located on your boot drive.
To disable Hibernate and delete hiberfil.sys:
1. Click the Orb (Start button).
2. Click All Programs.
3. Go into Accessories.
4. Right-click on Command Prompt.
5. Select Run as administrator.
6. When the UAC prompt appears, select Yes.
The Command window with the elevated command prompt will appear.
7. Execute the following at the command prompt:
powercfg.exe -h off
8. Restart your computer.
Now check your Primary Drtive Space..