Do you have Windows Movie Maker? Most installs of XP come with it.

http://www.microsoft.com/windows/win.../0075.mspx#EPD

If so, that link should help! If not...

http://www.dvdvideosoft.com/guides/m...P4-WMV-MOV.htm

That program will do it and I *believe* it's free, didn't look into it so could be wrong.