The OptiPlex 755 is a desktop computer from Dell used mostly in corporate and business environments. When work has to be done on the hardware of this computer, one of the first steps is to remove the front cover of the computer so that the internal components of the machine are easily accessible. While repairing the computer may require expert technical knowledge, removing the cover of the computer does not.
Turn off your OptiPlex 755.
Remove the power cable, monitor cable, mouse, keyboard and all other accessories from the back of the computer.
Lay the computer on its side.
Depress the latch on the interior of the computer, near the front, and pull the front cover off of the machine.
Ground yourself before handling any internal components.