XPS 420 Windows 7 - microphones is not working

Ever since I installed Windows 7 64-bit on my XPS 420 I have not been able to use my microphones that I can plug into the front.  I read that I need to download some drivers from Dell website in order to get them working.  I downloaded a driver for the chipset and tried to installed it but I always get this message telling me that there are no downloads and must be done in the drivers and devices.  I don't quite understand what that means or how to even install the drivers. Besides trying to install some drivers I also checked to see if the computer is finding my device when I plug it in and it does not.  I even went to the recording devices and right clicked the empty space and clicked, "show disabled devices."  Still my microphones do not show up.

I really need some help to figure how I can fix my problem with my microphones not working with my XPS 420.