Microphone Drivers

Greetings!

I have a Pentium D 830 with 845 chipset motherboard, running Windows XP
Professional. Audio drivers are Realtek Audio HD. I cannot get my
microphone volume level up to a useable level. I want to strip off the
Realtek Audio HD and go with the stock Windows XP audio drivers, but I can't
figure out how to remove the Realtek Audio HD Control Panel. Can anyone
tell me how to remove the Realtek Audio HD? (Yes, I tried the "add/remove
software" function on Control Panel)

Conversely, does anyone know how to increase the microphone record level
with Realtek HD? I've tried the standard volume features, but other than
one volume slider, all the volume controls are un-highlighted and
unaccessible.

Many thanks!
Max