free disk space in windows 7

Disable Hibernation

In Administrative command line, run "powercfg -h off"

C:\Windows\system32> dir c:\ /as
 Volume in drive C has no label.
 Volume Serial Number is 108A-ECA8

 Directory of c:\

03/07/2011  01:37 AM    <DIR>          $Recycle.Bin
07/14/2009  10:38 AM    <JUNCTION>     Documents and Settings [C:\Users]
06/27/2011  08:51 PM    <DIR>          found.000
11/03/2012  08:42 AM     4,824,846,336 hiberfil.sys
11/03/2012  08:42 AM     6,433,132,544 pagefile.sys
03/06/2011  07:57 PM    <DIR>          Recovery
11/01/2012  12:17 AM    <DIR>          System Volume Information
               2 File(s) 11,257,978,880 bytes
               5 Dir(s)   1,611,984,896 bytes free

C:\Windows\system32>powercfg -h off

C:\Windows\system32> dir c:\ /as
 Volume in drive C has no label.
 Volume Serial Number is 108A-ECA8

 Directory of c:\

03/07/2011  01:37 AM    <DIR>          $Recycle.Bin
07/14/2009  10:38 AM    <JUNCTION>     Documents and Settings [C:\Users]
06/27/2011  08:51 PM    <DIR>          found.000
11/03/2012  08:42 AM     6,433,132,544 pagefile.sys
03/06/2011  07:57 PM    <DIR>          Recovery
11/01/2012  12:17 AM    <DIR>          System Volume Information
               1 File(s)  6,433,132,544 bytes
               5 Dir(s)   6,436,814,848 bytes free

C:\Windows\system32>

In my case, it freed up ~5 GB disk space.

Paging file

Set C drive paging to none, set system managed paging on another drive.