Help! Microphone not working!

So I turned on my Inspiron E1505 and I find out my Microphone has stopped working. It's a headset mic I bought a while back, nothing special- just plug in and use. I used the microphone yesterday and everything was working fine. Now it's not working. I can hear everything fine, but the Mic does not work. I'm a teamspeak user and it doesn't work. Sound recorder doesn't work. I am running Vista 32 bit. I just got this laptop- I don't understand how it could work one day and not the next. I tried reinstalling drivers from the CD dell provided to no avail. Please help. Thanks, Chris