Assuming the microphone itself is switched on and plugged into the right socket of the sound card (been there, done that!), is it selected in the Windows "Record Control", with the volume up? The mic's live, even if it's not selected, but you can't record. Do you see any waveform on the audio track, or is it a flat line? If it's the former, have you muted the track? (I've done that, too!)
IM using mic built in computer it is on. It worked a while back but now it does not. I will check if track is muted.track line has noise only like static