Why can't I play music on my Q10?

i had to reset my Q10 and lost all data. i downloaded what i needed but i cannot play my music anymore. it says "this file contains an unsupported media" it never happened before

thank you for your help

Did you have a favorite Music Player App that needs to be loaded/installed? That being that you music files are in the same format as before....

thank you. i dont think i had an apps and just downloaded the same music from my computer but now music or even some videos are not working