no microphone and vista ultimate

I have a realtek ac97 sound card (on board). my wife sings with internet
karoke and we cant get the microphone to work at all. I bought a shure mic
instead of the (cheapo) computer mic. all the music and lyrics come thrugh
the speakers but when she goes to sing nothing comes out. we have tried to
congif it with all resources possible to no avail. any help????


thanks bob