Vista Mic Playback

I have windows vista. When I plug in a microphone, I can't hear myself in the
headphones. The vista mixer doesn't have a playback option for the mic. Any
info would be greatly appreciated. Not sure if I need to download drivers, or
just purchase a USB soundcard hoping it comes with software that will allow
me to control a different mixer. I was wondering if I could download and
install Windows XP or 98 so I will have the mic playback option.

I've done alot of net searching for this topic. I can't seem to find a
solution to the problem.