Microphone not working

[Aurorus20]

Plugged in my Afterglow Kral (USB) to use as a microphone, it picks up my voice on the 'Record' section of the settings, but cannot pick up my voice while trying to sing the actual songs.
Also tried an Official Singstar microphone, but that hardly picked up my voice.

Is there anything I've missed?

[Renard]

Hello! Did you try all steps in http://www.ultraguide.net/microphones.php ? Might also want to check your other Windows audio settings too, in case your mics volume is set too low.