Dell OptiPlex 755 User Manual page 256

2
2 If the module bay contains a device that is locked with the locking switch, remove the cover (see
"Removing the Computer Cover" on page 232) and lift the module locking switch to the unlocked
position. If a security screw is also used, remove the screw.
256
Module Bay
1
bottom of computer
2 security screw
1