No audio output device is installed

Hello,

For no reason (I'm guessing my windows done an upgrade on its own) my sound will not work. The speaker in the bottom left has a big red 'X' and when I hover over it I get the message "".

Now I've scoured the internet and what seems to work for most people is to go through Device Manager and select 'sound, video and game controllers'. However, My device manager does not even have this. I found somewhere else that I should install some drivers from the HP website, but when I tried to install them I get a pop up box with the error message "Driver Installation Failed: Could Not Find The MEDIA device for this driver".

So I'm at a complete loss. Does anybody have any sort of help they can think of?

Thanks,
Tom.


Specs: HP Pavilion dv6500
Windows Vista