The installer for WMP9 carries warnings that it CANNOT be removed once
installed. Your only recourse is to do a repair installation and then
re-apply all the patches & SP1 that you've previously installed.
To do a repair installation, boot from your XP CD and choose the Install
option, it will then detect if you have an existing installation and ask if
you want to repair it. Note: To do this you need a PROPER XP disc, not a
restore disc. If you only have one of those, they you'll have to backup what
you need and do a factory restore.
Also, instead of using the Nero WMP plugin, try downloading the full Nero
program and using that instead. CD burning in XP is very limited and Nero
is SOOO much more powerfull & flexible. They have a 30 trial version you
can try...
Lorne