There are only 2 SP for XP PRO. The solution is to get a friend to burn you a copy of their disk onto a CD. This is perfectly legal since all the disks are the same. It is the liscence key that is what you are really buying.
If you have lost your key along with the disk you can read your key off of your system using a freeware download.
If you have no friends with XP Pro, then try the place you bought the computer from. MS will supply a CD replacement if you bought and registered a commercial version (for a fee, $25 I think).
Oh, office XP. Same deal MS will sell a replacement disk for registered product. It will be a lot harder to find someone with a copy of Office but still the same applies. Just burn a copy of the same version you bought.