When your XP installs updates, it also makes a backup of the original settings and adds an uninstaller for the update, so that you can backtrack if the updates cause problems, these are the files you are looking at. If however your system is stable and you're happy to clear some space and don't need to backtrack, you can run click here xp_remove_hotfix_backup and clean them out. As the free version doesn't allow selection of what file to clear and wipes the lot, it's not a good idea to run just after an update. Wait a few days to make sure everythings OK before cleaning them out.
If you're not short of drive space, then the benfits of clearing them may be marginal, your call.