Best/easiest way to convert wma files?

If you’re comfortable using command line Windows Audio Lossless to Wave Converter will do it as a batch job. You can download it from Microsoft. 

Thanks Al
Just completed a test batch of 500 converted to flac and all is well!
Reads them just fine now so.....
only 94,500 to go......

Linux. Ffmpeg. Free.

Using the trial version of sound forge pro as Al suggested.
First test batch of 500 went well and did exactly as I wanted.
Started the complete hard drive conversion last night, 12 hours completed, 11 hours to go... lol.

Uber, it looks like you have this figured out, but foobar2000 will also do batch conversions and it is free.  I use it to rip CD's and listen to all the music on my network.