HP L1755 User Manual page 14

Setting Up the Monitor
2. For analog operation, connect one end of the VGA signal
cable or the VGA to DVI signal cable to the VGA connector
on the monitor and the other end to the VGA connector on the
computer. For digital operation (available on select models),
use the DVI-D signal cable. These cables are provided with
the monitor.
Connecting the VGA Signal Cable
User Guide 3–5