armada e500

I recently purchased a compaq armada e500. I have windows xp
professional installed. I am having a few problems and am hoping
someone can help me. First of all the volume control buttons on the
front have no effect on the system volume. Secondly I have no way of
adjusting the sensitivity of the touchpad. Thirdly the extended
function keys ie. screen brightness etc., do not work. I am unable to
control brightness etc. Thanks in advance for your help.

Regards,
Marbo