Microphone

Im sure everyone has that little hole on top of their monitor right? well my computer came with a microphone and it worked well. One day i tried connecting a new microphone to my pc. i finally decided to go back to the stock microphone, but to my suprise it didnt work. ive even installed windows again to see if it worked, but it didnt help. anyone have any idea what to do? i know its a pretty dumb thing for me to ask, but i really use the microphone, so if anyone can help me thanks.

Try another microphone? Check Windows audio input settings (NOT THE OUTPUT settings, it looks identical), make sure that the microphone MUTE box is not checked.