Guitar Hero Mic not working - mic not recognised.

Had Guitar Hero for about a year now and bought the microphone afterwards.

Its always been a little tricky but they have both worked until now. The microphone just is not recognised. When it starts up it sees that a microphone is plug in but then once we choose the songs it says "a microphone needs to be connected".

We have tried everything, used all 4 hand remotes, unplugged it, reset, put mic in before, middle and after.

Its just not working.

If anyone can help please email in.