Use the Dell website. With big names like Dell and Packard Bell you need to use their respective websites to get the correct drivers as they are often 'non-standard' to match their customised hardware. You need the 'audio driver' (also called a 'sound driver') for your specific computer model. If your PC has a 'tag number' on the back (or underneath for a laptop) you can enter that, or click on "Choose by model".
For the UK go here:
http://support.euro.dell.com/support...=uk&l=en&s=gen