Windows XP has an equalizer in the control panel
WRONG! That depends on your sound card and its driver!
Some dont have that option in the windows control panel....and its not a
standard part of windows.
Most modern audio applications (winamp, windows media player etc) have
equalizers....
And I have seen a software universal equalizer for every sound comming from
your pc...
(but when I tested this some years ago, it was not working so well).
Kenny