Windows Media Player 9.0 and Codec reinstall?

Archived from groups: rec.video.desktop (More info?)

I downloaded an AVI video in the divx 5 format. I tried to play it,
but the video freezes after a few seconds, audio continues. The same
thing happens when I open it up under mplayer2.exe. So I uninstall
divx and reinstall under the admin account Media player 9 and divx.
Same thing. I'm running Windows 2000 SP4 with all the updates and a
2.8Ghz machine with a gig of ram. I transferred the files to another
almost identical machine - same specs different motherboard and it
played them fine. On that machine I was able to use tmpgenc to
convert them to mpg and play them just fine on both machines.
On the second machine when it tried to access the original AVI file it
brought up Apple's Quicktime saying it was missing a critical
component. I uninstalled it, and Tmpgenc worked fine. I think
Quicktime tries to screw around with some stuff it really shouldn't
be. Divx and QT are completely independent of each other. Right?

So my question is, how can I do a "mini reformat" of Media player?
Get rid of all my codecs and start from scratch? I think I have a
nasty codec in there somewhere that won't go away. The second machine
is the one my dad usually used (despite my building it) so it didn't
get very many codecs installed on it at all- and it was fine.
Thanks!