Convert WMA audio files
From Help Wiki
What is a WMA file?
Windows Media Audio (WMA) is an audio data compression technology developed by Microsoft. See en.wikipedia.org/wiki/.wma It is also the default file format for the Olympus Digital recorders available through media loan.
How do I convert WMA files to something useful?
Windows
You don't need to convert these files as they are native to Windows and will play under Express Scribe.
Macintosh
You will need to convert these files before you can bring them into other programs.
Online Media file conversion
If none of the above works for you there's always mediaconverter.org, a handy, free site where you can convert media files to and from almost every useful format. It's a bit slow, and you can't do batch conversion, but it'll work in a pinch.