I purchased a compaq - type# g80-11802lpaus/03 part#185152-406 rackmount keyboard and the intigrated trackball will not work on the machine I had intended for it's use? I hooked the keyboard up to another machine and it works fine? Both machines have the same OS Xp Pro, same updates and same programs? On the machine that will not respond to the trackball, the device manager indicates that the mouse is operating properly? BOY THIS ONE HAS ME AT A LOSS!