That's a setting in the Power Options in Control Panel for most of us.
http://www.howtogeek.com/howto/7564/how-to-manage-hibernate-mode-in-windows-7/ gives alteratives if you don't like Control Panel.
Kees
i just had a out side person tune my comp. up really didn't help but in the process he turned off my hibernate mode i use this for a couple of hours when i take a break my question is how do i get it back i have looked please help and thanks

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic