Are you talking about the sort of generic version of XP that came before the division of Home and Pro? Was it called Office Edition?
And unless your installation was an "upgrade" you will not get it back unless you have the original CDs.
hi, I have windows XP Pro installed on my laptop but I am not happy with it and I would like to revert to my old windows XP, however the computer does not let me install my basic windows XP again as it says that Pro is newer. So please can someone tell me how I can un-install XP Pro and reinstall XP?