If you want to convert MP4 to WMV , google the free converter tool, you will find a lot. most of them are bundled with spams.
I just find this one, which is free and free of spams. http://www.pcfreetime.com/ Format Factory.
it supports a lot file format.
Format Factory is a multifunctional media converter.
Provides functions below:
All to MP4/3GP/MPG/AVI/WMV/FLV/SWF.
All to MP3/WMA/AMR/OGG/AAC/WAV.
All to JPG/BMP/PNG/TIF/ICO/GIF/TGA.
Rip DVD to video file , Rip Music CD to audio file.
MP4 files support iPod/iPhone/PSP/BlackBerry format.
Supports RMVB,Watermark, AV Mux.
Format Factory's Feature:
1 support converting all popular video,audio,picture formats to others.
2 Repair damaged video and audio file.
3 Reducing Multimedia file size.
4 Support iphone,ipod multimedia file formats.
5 Picture converting supports Zoom,Rotate/Flip,tags.
6 DVD Ripper.
7 Supports 56 languages