If you want to edit your wmv-videos (cut commercials)
you may use MS Movie Maker which is part of SP2-MS Windows:
On a german XP System you find the file here:
c:/Programme/Movie Maker/moviemk.exe
(copy string into Start->Ausführen)
or on english systems: c:/program files/Movie Maker/moviemk.exe
(copy string into Start->Run)