.WMV format can be preconverted and drag and dropped onto the zune software without converting.
Unless you've done something wrong with the converting process, zune software shouldn't convert anything for you.
If you're unsure of the procedure of converting media to .wmv files, please follow my guide.
http://www.zuneboards.com/forums/tut...es-faster.html
or many other guides in the tutorial section.
http://www.zuneboards.com/forums/tutorials-97/