Good day Alan, thanks for your question. I am glad to be able to provide assistance to you today. You can try this, open Windows Media Player and open the WMA file that needs be converted and then select the 'Organize' option on the top bar and then click 'Options' and then followed by 'Rip Music' and from there you can choose where you save the file to and after that you need to select 'MP3' in the 'Format' section which is under 'Rip settings'.
Regards,
Paul R.