lynchknot when you start to boot up keep hitting F-8 you'll come to some options...

Try boot into Safe Mode with Command prompt , type in sfc /scannow , make sure there's a space between sfc and the /
or try just sfc and you should get a list of options.

Can also try Last Known Good , anyway you'll see the options just give um a try. If these don't work you'll need to do a repair unless someone comes by with other ways for a fix , I've never crashed XP so these are all I know about. In most cases I'm sure you need the XP CD...hope you have one

BTW when you get going post a pic of your WebTv desktop....J/K ...wish you well

[edit]= sorry guess I should post reply before eating dinner...Thanks Conan