MP3 Files Will Not Play

Good morning,

I recently went over to my parents because my sister was having a problem with her computer. She downloads music and has iTunes. She had to reboot her computer from installing software, and once she did, all of her music files give her an error and won’t play. Everyone, over 100. When I looked into the error, it said that there was a problem with the sound device. So I did a Windows Update, and found updates for her device, and now, she has no sound from anything. What could have caused the music files from not playing? There was no license limit on them or restrictions.