its a lenthy process....and pretty dangerous to the system if done wrong....and you need a binary file editor (or hex editor) to alter a critical Windows system file, it is therefore not recommended for inexperienced users.. but if you are up to it, then this site here will assist you further. make sure you make backups, and it does go a little easier on XP Pro then XP Home...with Pro, you can add more then 5 letters, with Home, you're stuck with 5 letters only, and works better with SP1 rather the SP2!