No Audio

I just recently installed a Logitech webcam to my mothers ACER computer
w/VISTA. The camera is working beautifully, but I have no Audio to talk with
family on YAHOO Messenger. I installed and uninstalled then re-installed and
followed the instructions very carefully and still I have nothing. When I
test the built in mic the sound scale goes to the green color as instructed.
Then when I go Conference with YAHOO, the TALK button is not lite up for use.
I have been told that Microsoft/YAHOO would release a fix by the end of June,
2007. I am unable to locate a fix/update through Microsoft or YAHOO>. Please
let me know where I can go to correct this problem and fix my Mother's
computer. Thank you so much for your time & help!

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kthymarkham