You know, I've had a problem since I installed Vent where my mic doesn't work. However, uninstalling it has done nothing. I'm still trying to trace it down (not muted), but I may just give up and reload my system. It's near time anyways.
Jackpot was having this porblem and he had it in the system volume where his mic was muted, so just check ALL of your volume settings if not I would check to make sure that the mic is set up to run with your computer, I have had it to where it switches to the default setting for a mic(for me that's none) and I have to switch it occasionally. BUt I hope it gets back to working soon! ^^