Best/easiest way to convert wma files?


I have about 95,000 wma music files on a 2tb USB drive that my Aurender N100 cannot read.
Any suggestions for converting them or is that a non starter?
Many thanks.
uberwaltz
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.
The Windows Audio Lossless to Wave Converter is free as well. It's mainly for converting wma to wav. It might have  done it slightly faster since it doesn't have a GUI but any that gets  the job done is all that counts.
Djones.
I have all the great suggestions saved, it is much appreciated.

Tbh, the time is no biggie as off this week and just letting it do its thing in the background.
I think flac files take up less space than wav though.
And it looks like my 239gb WMA files converted to flac is still going to overflow the 2tb hard drive!
Just bought a 4tb hard drive to transfer to later.
All done and now have over 6000 albums to explore.
Quick glances show not too many duplicate of my own collection.
Enough to last me a few evenings I would say.......

Thank the Lord for CMD batch file extension delete to get rid of all the left over WMA files on the drive.
Less than 30 seconds for the PC to wipe out 95000 WMA files , impressed!