1.First you should enable administrator account in windows 7, Then login with administrator account
2.Now Start to move your user data folder to a non-system partition such as D:\userdata. You Relocate your user data to other non-system partion,for example from C:\users\w7 to D:\userdata.
3.Create a symbolic link by mklink command:
mklink /D C:\Users\J D:\users\J
4.Logoff and login your own accout. Now your physical user data is on drive D.