'Switch Sound File Converter' is the easiest one I have come across and it also does Batch Conversion - ie several files at once. It can do conversions to and from most Audio Formats and it's free
http://www.nch.com.au/switch/index_b.html?gclid=CJD9yIPvmaACFRQulAodghjndw

During installation, you will be asked if you would like to add extra programs from a list. If you don't want them, just don't tick the boxes.......

Have Fun!
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Willum

After silence, that which comes nearest to expressing the inexpressible is Music.
Aldous Huxley
( especially when the music is played on a KN7000....)