I didn't know it was possible to record with WMP. Anyway, Media Players 7 and up have digital rights management built in and that can interfere with editing.
It's possible you need newer WMV codecs, but those come with the latest versions of WMP so you should already have them. If not, check this link -
Microsoft's Codec page
Fav quote - "Experience is whatcha don't get 'till ya don't need it no more."
System - Athlon 1.4GHz, Win98, Hauppauge PVR250 receiver and compressor.
Software -Magix Movie Edit Pro 10, Nero 6 + NeroVision Express, Moho 4.61, PSP 8.1, Bryce, Quicktime 6.52 pro, Goldwave 5, DVD-Lab.
Cameras - Panasonic GS9, Canon ES8400V, Canon EOS D20 and Canon A70