I believe it depends on the circumstances, of course you can find legit WMA files, which are songs ripped via Windows Media Player, however majority need licenses to play them, the same is with WMV and MOV, these are also to do with majority brand video players Windows Media Player and QuickTime.

With Anti-Virus, Spyware, and Firewalls, I would suggest trying something that you can feel comfortable using, and is somewhat user friendly.