Compaq 247320-003 - Deskpro 4000 - 5166 Model 2500/CDS Reference Manual page 168

Problem
Computer won't turn on
Computer doesn't
automatically display the
date and time
Computer does not beep
during the power-on self-
test (POST)
Check all cable connections for loose connections or
incorrect connections.
Check that all switch settings have been set as instructed by
the Configuration utility.
Be sure that all the needed device drivers have been
installed (for example, if you are using a mouse, you need a
mouse device driver).
Make sure that all printer drivers have been installed for
each application.
Take out all diskettes from the diskette drives before you
turn on your system.
While your computer is configured for your particular hardware
and software, problems you encounter while working may not
be unique. Eliminating the typical problems described in this
section may save you time and money. If you do have a
problem with your computer, consider the problems and
possible solutions outlined in the following series of tables. You
may discover something you can resolve easily for yourself. If
the condition persists, contact your Compaq authorized reseller
or service provider.
Cause
Computer is not connected to
an external power source.
Cables to the external power
source are unplugged.
A defective PCI or ISA card
has been installed.
RTC (real-time clock) battery
may need to be replaced.
Battery life is approximately 5
years.
Speaker volume has been
turned down.
Solution
Connect to an external power source.
Ensure that cables connecting the
computer and the external source are
plugged in properly.
Remove any adapter card that was
just installed.
Replace the RTC battery. Refer to
Appendix G, "New Battery
Installation," for installation
instructions, or contact your Compaq
authorized reseller or service provider
for RTC battery replacement.
Click Start, then select Programs,
Accessories, Multimedia, Volume
Control.