If you have the ability to back up every important file on your computer - and still have the original OS Cds, you should REALLY consider doing a fresh install of XP. If your system is loaded with random stuff, has had lots of programs installed and uninstalled over the years and wavering problems with programs - a clean install is the way to go. Format everything. Start over. Install all the windows updates -- and transport programs in again, and all the files you saved.