If you have purchased DRM-protected files legally, the you should ask your content provider how to re-acquire licenses. If your content provider is not available anymore or can't help you with re-acquiring licenses, there is nothing you can do...

p.s. If your content provider was using the same SID/KID for the WMV files, you can try to find these values in the Internet. MD5 checksum of the file may help you in this case.