Hello Bob,
Welcome to Microsoft Community. I will certainly help you with the issue that you are facing.
You may try to reset the DRM store on the computer and check if it helps you fix the issue. To do this, follow these steps:
a. Locate the DRM folder on the hard disk, and then rename the DRM folder to DRMbackup.
Note: By default, this folder is in the following location in Windows 8: %SystemDrive%\ProgramData\Microsoft\Windows\DRM
b. Visit the following Microsoft Web site:
http://drmlicense.one.microsoft.com/Indivsite/en/indivit.asp
c. Follow the instructions on the Web site to update the security component of Windows Media Player. This procedure enables you to obtain new licenses for media content. You can also reset licenses for purchased content so that you can play that content on
a computer.
Note: On a Windows 8-based computer, you must run Internet Explorer as an administrator before you update the security component of Windows Media Player. To do this, follow these steps:
If issue still persists, follow the link and check:
A license is required to play this file
http://drmlicense.one.microsoft.com/pdrm/en/welcome.asp
Hope this information helps.