NEC READY ES PRO Manual page 21

2.
all the way to the front panel, place one hand on the front
of the unit while you slide the cover forward from the rear.
3.
4.
5.
6.
14 A look inside
Slide the cover forward to meet the front panel.
Note:
The cover fits tightly. If the cover does not slide
Secure the cover with the three cover screws removed earlier
(see "Taking off the cover").
If you have a cover lock, replace it and secure it.
Connect the monitor, keyboard, mouse, and any other external
devices to the back of the system unit.
Plug in your power cables.