Windows Vista "No Audio Output Device Installed"

I was given an old PC a few days ago. Everything runs fine on it apart from the sound. When I hover over or click the volume button, it says "No Audio Output Device Installed". The PC is running Windows Vista Home Premium 32 bit. The guy who gave it to me wiped it completely before giving it to me, so there was a little setting up to do (updates and such) and finding drivers for the WiFi card. I have done everything required up to this point, and I am completely defeated. I have tried several things, including:

-Uninstalling the driver and restarting the PC
-Manually finding drivers
-Let windows search the internet for the right drivers (all was up to date)
-Deactivating and reactivating the device

None of them have worked. I have looked on the internet for different solutions, but these seem to be the only ones anyone seems to offer, and it also appears that a lot of people have the same problem as me.

In device manager, under Sound, video and game controllers, the only thing listed is High Definition Audio Device. All of the drivers are up to date for it, and everything seems to be in working order.

It may help to know that the PC was built, not bought from a shop because some solutions I am seeing are brand specific and are of no use to me.

Help?

Thanks