When the final version of SP2 is released, it will not install over
a beta version of SP2. You'll have to uninstall SP2-RC1 as a
prerequisite to installing the final version of SP2. If you experience
difficulty uninstalling SP2-RC1, then a "Clean Install" of Windows XP
will be required, although a "Repair Install" may be a viable alternative.
--
Carey Frisch
Microsoft MVP
Windows XP - Shell/User