Figured it out.
Apparently, sometimes the OP+4.0 installer might hang or something, as windows generally always seems to do once and while, but in my case, it happened while it was rewriting the sound file to fix the ESG loop or whatever it is, the installer puts a back up copy in your folder for you, just have to delete the .orig from the end and you get your sound back.
Hope it helps anyone who might be having the same problem.