Brewer dood I have had all shades of disasters with codec's over the years.

Sure keep Windows media player if you wish but you really should download and install the K Lite codec pack. Copes with just about anything... even FLV's

available here:
http://www.k-litecodecpack.com/

but prob better from here:
http://home.hccnet.nl/h.edskes/mirror.htm

make sure to get the:
http://finalbuilds.edskes.net/klmcodec.htm
version.

Keep it up to date and you will be able to play almost anything AND make great screen caps easily.

Hope that helps.