The unit has two sets of two USB ports. Each port is marked. One for the keyboard, another for the mouse, a third for the ethernet, and the forth for the printer. If I put the USB DVD/CDRW in the mouse port, and the keyboard in the printer port, I see the USB driver loading, and the CD is recognized. For both Centos 4.5 and 5.0 I have submitted a bug report on the Centos 5 crash further into the install.....