Freemake video converter is the bomb, it converts almost every video format. I use it all the time, how ever it does create useless folders in your documents folder and c:\
You do have to have the codecs for the one you're converting from to the format you're converting to.
This package has them all. Just run it as is and don't make any changes to it. CCCP - Combined Community Codec Pack
Don't mind the splash page. It's just a humorous poke at the letters in the name of the program.