I tried another mic, and that one works so I guess it's the headset at fault.
I wish I'd kept the receipt!
When I tap it, it responds on the hardware test wizard but it's only barely picking up my voice... which is strange, because the second microphone that I tried had the same problem last year! so now the old one works and the new one doesn't.
Oh well, I guess I'll just have to go and buy another one.
Thanks HVAC
