I recommend removing the card from the system. Make sure the computer is OFF when you do so!!!! As far as the onboard audio goes--go to dell's website and look up your system in Drivers and Downloads. You can use your service tag number (white one) on the back of your chassis. It may give you more than one option for sound drivers.
I can't do more right now (going to work on computers
) but if you need more help say so. There are many on this site who will be happy to help you. And I'll be online at work as well and try to point you in the right direction.
Don't give up the ship!!!!
Peto