Dell OptiPlex 740 Guide De Référence Rapide page 11

You must complete all the steps to properly set up your computer. See the
appropriate figures that follow the instructions.
NOTICE:
Do not attempt to operate a PS/2 mouse and a USB mouse
simultaneously.
1 Connect the keyboard and mouse.
NOTICE:
Do not connect a telephone line to the network adapter connector.
Voltage from telephone communications can cause damage to the network adapter.
2 Connect the telephone line or network cable.
Insert the network cable, not the telephone line, into the network
connector. If you have an optional modem, connect the telephone line to
the modem.
3 Connect the monitor using ONLY ONE of the following cables: the white
DVI cable or the blue VGA cable (do not connect both cables to the same
computer).
Align and gently insert the monitor cable to avoid bending connector pins.
Tighten the thumbscrews on the cable connectors.
NOTE:
screen. See the documentation that came with your monitor for its connector
locations.
Some monitors have the video connector underneath the back of the
Quick Reference Guide
11