Ahh no big deal!
Just wish you luck, if you do run into crazy issues or just cant get it and we are both around here I can connect to you if you want me to, and see about getting it done for ya from my end. If you think you may want to go that route, please download SP3 Standalone installer and have it ready, Ill remove all your previous updates and just install it >>>
Download details: Windows XP Service Pack 3 Network Installation Package for IT Professionals and Developers