HELP! No audio device/driver installed??

Hey.

So I have an Acer Aspire 6920 and Windows Vista and recently, all sound was lost. I tried plugging in different speakers and headsets and still no sound was powering through. In the bottom right of the screen, there is a speaker with a red X saying that NO AUDIO OUTPUT DEVICE IS INSTALLED. So I went on Google and searched for resolutions and most of them suggested uninstalling and reinstalling the driver.

My sound drive is Realtek, so when I went to Control Panel>Device Manager>Sound, video, and game controllers, there is no Realtek drive that I can try uninstalling. The only thing in the drop down menu is AVerMedia A309 Mini Card.

Also, when I turn on my laptop, a message appears saying To enable sound, you must install Realtek driver. Does this mean my sound card burned out? Can anyone help a girl out? Thanks :)