Ati high definition audio device driver expired?

Basically, my sound won't work and after some investigating I found out that it was because my audio drivers aren't being recognized by Windows. Based on some Googling, I came to the conclusion that they've outlived their license. I've tried turning off driver signing on boot up, but not only is it not permanent, I now can't seem to get to the screen when I boot up the computer. Can somebody help with this?