I need to edit a wma movie and put another sound file on it. I tried live movie maker but it sucks and freezes whenever I try to add animations.

Is there any free program that can convert the wma file to maby mpeg2 and then a free program where I can edit the mpeg2 file and add my wav?

Saw some trial programs but they added a watermark on the movie and I dont want that.

Kind regards