Dell OptiPlex SX270N - Manual (Page 15)

To remove the chassis stand, loosen and lift the screw. Hold the screw up while sliding the stand out of the slot.
Cable Cover
Attaching the Cable Cover
3 mounting slot (for vertical position, upright on a desktop)
4 mounting slot (for horizontal position hanging under a desktop)
NOTE: The stand must not be used in the horizontal position on a desktop. Place the computer directly on a desktop.
5 mounting slot (for vertical position, hanging under a surface)
NOTICE: If you are installing the computer under a desktop or tabletop, do not attach the cable cover until the computer is firmly attached to the
mounting plate (see " Attaching the Computer to the Mounting Plate ").
NOTE: If you use the stand on your computer, attach the stand before attaching the cable cover.