Delete the "hiberfil.sys" to recover HDD space in windows 7

Critical detail: Right-click Command Prompt and select "Run as administrator"

So follow the step-by-step instructions:

1) Click Start -> All Programs -> Accessories
2) Right-click Command Prompt
3) Select Run as administrator
4) Grant admin permisssion to change system settings
5) In this "privileged" command prompt window,

   enter the command prompt:  powercfg -h off

That's it!  Now "hiberfil.sys"  is gone -- instantly!

Cheers!