This is a pretty common problem for me, and several people I have seen around the net. With a supper simple fix. What this is, is where you laptop says you have no audio device. The only sound that works is that annoying system beep sound. All your drivers are fine…Here is the problem:

YOU SOUND CARD CAME UNDONE!

Yes, it is that simple. And the fix? Shutdown your laptop, and light (VERY LIGHTLY) tap the back, near the hinges, on a flat, hard surface. That should get your sound card back in place. Reboot, and check. If it isn’t working still, you might have to open up the laptop, and push it in yourself.

Hope this helps someone!