i have already face this problem.
the solution of this problem is that, first go to link which are given below.
ftp://ftp.hp.com/pub/softpaq/sp32501-33000/sp32646.exe copy this link and paste it to the web browser, then automatically downloading start.
and then install this downloaded driver into your pc/lappi and then install your audio driver .
also now if you have any problem then also paste the link into the web browser which are given below.
ftp://ftp.hp.com/pub/softpaq/sp32501-33000/sp32686.exe donload automattically start .
then install your audio driver.
it is sure that you will find that the problem is solve.........
The most updated audio drivers for Vostro Notebook A840 can be downloaded from here. Also, you must follow the correct order of Drivers Installation after Operating System Reinstallation for all the hardware to function properly. Click here to find the correct order of drivers installation.
My Dell A840 laptop came with Windows Vista Basic Edition and I downgraded it to Windows XP Pro lately post which I faced issue with audio drivers even after using the Dell driver CD/DVD which came with the laptop.
Issue: Laptop had sound problem (i.e. Audio drivers were not detecting hardware).
Symptoms: On installing driver was getting error "Driver Installation Failed: Could not find the MEDIA device for this device".
SOLUTION:Here are the two steps I followed to fix the issue: