If you are using XFree86 for X-display, then try editing your configuration file at: -
/etc/X11/XF86Config-4
Try copy the section of your "InputDevice" for mouse where it used to work in your Mandrake 8.1 configuration file to your 8.2.
It look something like this: -
Section "InputDevice"
Identifier "Mouse0"
Driver "mouse"
Option "Device" "/dev/mouse"
Option "Protocol" "PS/2"
Option "Emulate3Buttons" "yes"
Option "ZAxisMapping" "4 5"
EndSection
Hope this helps.
