Your question begs a lot more information. And the fact you didn't include that info in the original request may be the reason you aren't getting any responses. I may be wrong but you may be in the little knowledge is dangerous category.
At it's most basic you can reformat the drive/drives.
But you need to tell us where these versions of XP are loaded - is the hard drive patitioned? & the mind boggles at the thought that these are all separate legit licenses!
You may be in danger of losing programs that you don't have back ups for if you reformat.
That said it is a good idea to reformat say once a year just to clean up the detritus. But even with an XP Pro with SP2 to reload everything including all updates will take you the best part of a day - even if you know where all your program CD's and driver disks are.