snowmman

Assuming the speaker icon is visible in your system tray:
Double click on it.
Click on Options tab,
select Properties

You should get a popup window

click the button next to Recording
under "Adjust Volume For"

Click Ok.

That window will close, and you'll
now have the Recording Control window

Assume the microphone slider is visible,
with no Advanced button under it.

Go to Options in the Recording Control
window, and select "Advanced Controls"
(a check will appear next to it)

Now you should see an Advanced button
under the microphone volume slider
(I'm assuming your microphone volume slider
is all the way up in this window, and there
is a green check mark in the Select box
under it)

Click on that Advanced Button

What you see now is a new window, and it is vendor specific,
I believe. You should see a Microphone
Boost, or +20DB thing this new window.
Click next to it to get a green check mark

click Ok and close all windows.

test using the windows sound recorder or whatever you've been
testing with.