Convert wmv file to mp4 file

I have a "[login to view URL]" file that has been created using the goToMeeting codec that they have on their website. After doing a webinar, this recorded file is produced <filename>.wmv I want this file converted into an MP4 file through some conversion process done on my computer. (recording it via the screen or using a screen capture program with audio in is not an option) it must be converted using a program. There are audio (sound) and visual video that is inside of these wmv files and the recording, but audio and visual must stay in tact. The quality of the video must be the same as well. I will provide a sample file on request. Its about 100MB and its around 45 min in length. I need to have it converted into an MP4 with video and sound. At the end of this project I need to have a step by step guide on how you converted the video, as well as a copy of the video converted.