HP Deskpro 1000 Reference Manual page 47

Solving Display Problems
Problem
Screen goes blank
The picture is broken
up, or it rolls, jitters, or
blinks
Monitor overheats
Cursor will not move
using the arrow keys
on the keypad
6-8 Troubleshooting
Continued
Cause
You may have a screen
blanking utility installed or
energy saver features are
enabled.
The monitor connections may
be incomplete or the monitor
may be incorrectly adjusted.
There is not enough ventilation
space for proper airflow.
The Num Lock key may be on.
Solution
Press any key or type the password.
1. Be sure the monitor cable is securely
connected to the computer.
2. In a 2-monitor system or if another monitor
is in close proximity, be sure the monitors
are not interfering with each other's
electromagnetic field by moving them
apart.
Leave at least 3 inches (7.6 cm) of ventilation
space. Be sure there is nothing sitting on top of
the monitor obstructing the air flow.
Press the Num Lock key. The light should not
be on if you want to use the arrow keys.