You can't really delete ALL your personnal data. I think you have already deleted My Documents, My Pictures, My music , My Video. You can use CCleaner to delete hisotry of IE , Cache and many traces of standard programs ... You can create a new user (session) and after login with this, and delete the old account, and delete the old account in Documents & Settings too. But it's not cleaned fully, you don't know where some personal data is stored. There are always traces ... The best is to format/reinstall (or restore/master) the system.