SP2 contains numerous security enhancements over SP1, and so ANY XP system that will be connected to the Internet should be running SP2. Otherwise, you intentionally leave yourself open to many known exploits, and are just gagging to get your system turned into a pirated software dump site if you have broadband, or a zombie system which is used to perform illegal activities.

Get rid of the SP1 install, not SP2. Or install SP2 on the SP1 install.