My uncle said there was an update or something, and now a bunch of his Harry Potter audiobooks won't play in Windows Media Player. I tried using VLC but it had the same issue with the exact same files. On top of that, Windows throws an error on login saying that avastui.exe could not start, so the Antivirus isn't working. We tried restoring the system to a point where it did work but it didn't do anything. Anyone know the cause of this or at least how to fix it?