How do you change all document folder names in your computer?

My user name is right, but my grandfather named all my documents and pictures by my cousins name, i want to change that, how do i do it? example, if the name was C:\Documents and Settings\Amber . how do i change the name?How do you change all document folder names in your computer?
http://lmgtfy.com/?q=rename+user+folder+



and don't let your grandpops on your computer next time.