I purchased a microphone for my desktop, and after not being able to get it to WORK, I exchanged it at the store. The store TRIED out both mics on their computers and they worked fine. I have gone through all the regular troubleshooting (it's not muted, it's plugged into the right port, I've tried sound recorder and skype and the control panel hardware setup, etc) and nothing seems to be working.

I’m running windows XP – not sure of the exact stats of my computer but it’s about 3 years old and has average stats, around 80 gigs. My soundcard is VINYL AC'97 Codec Combo Driver (WDM) and the one thing I noticed is in the Control Panel audio options, the Vinyl AC'97 (WAVE) is the default mic device, and the other options are greyed out.

The mic is a very very basic nexxtech mic that came with no software or drivers.

Thanks, I hope you can help.
Look for a SETTING called "Microphone Boost" or something similar.  If not enabled, then enable it.  I got it to work by playing around with the settings somehow. I think updating the sound card drivers did it. Yay! Thank you.