The OP actually does give us enough information to give us a good idea where the problem lies. It's software not hardware.
The "Not available" message (as opposed to "Not plugged in") tells us that the first place you should look is settings in Windows.
If we saw this, then yes, I would assume the mic (or possibly the PC's mic jack) had a bad connection:
- Enable hidden audio devices (right click in the "Recording" window in the Sound options screen)
- Set the external mic as default
- Disconnect then reconnect your mic to see if it changes status
Failing that, you can also try setting another device as the default recording device, then set the mic as the default again- as well as disabling the mic, then re-enabling it again. Also, any 3rd party audio software, or audio drivers should be uninstalled and reinstalled as a last resort. Take a quick look in Device Manager and make sure the audio drivers aren't showing any errors.