Okay here it is from Microsoft for KB833989 see this page http://www.microsoft.com/technet/sec.../ms04-028.mspx Scroll down to General Information...Expand "Security Update Information" by clicking the plus sign. Click the plus sign beside "Windows XP, Window XP Service Pack 1". In here you will see switches which can be applied to the service pack including /uninstall.
Next 873374
This is a run once tool..it is strictly an executable which is not installed to your registry in anyway and therefore can not affect your system unless it is actually running. It just does a scan the one time to recommend other updates.