My laptop says no audio device is installed

Hello,

My computer had a little crash in which it lost all my personal files and since then my computer has had no sound and this is the message I have been getting "no audio device is installed" and there is a red sign with an x on the place where you can adjust your volume.

I have tried to do the following based on the advice I got using Google:
- I have tried to uninstall the driver to let the computer find it on its own and re-install it
- I have redownloaded the driver from the manufacturers website
- I have tried to update the driver and I have also checked that it is enabled
- The speakers look fine and I have also tried to scan for hardware changes without luck.

Is there anything else I can do to get the sound on my laptop back? the computer is working fine and everything I use seems to be ok except the fact that the computer now has no sound. I am using an acer laptop with windows vista if that helps

Thank you