Sound Blaster Audigy Advanced MB sound card/Will not record sound??

First, the "Sound Blaster Audigy Advanced MB" is NOT your sound card. It is only a software enhancement to the basic Integrated (on the motherboard) audio and your case the audio is the "SigmaTel" audio that is used on many Dell's (and other PC Vendors).  Sorry to tell you of your misconception.

What kind of mic are you using?  You must use a "computer" mic.  Have you tried both the front and rear mic jacks?  On some models there is a setup in the Control Panel/Sounds for the front or rear mic connection.   There is also an issue with SOME models with Vista that it will actually record but you can't monitor (hear on the PC speakers) the mic sounds.  

Hi cbern,Your better off buying an Creative Sound Blaster sound card, they are a lot better than the onboard sound. See HERE