Dell Dimension 2100 System Reference Manual page 17

Power up default.
System board is
receiving power, but
the BIOS is not
executing.
Make sure that the
computer is connected to
a known working
electrical outlet, and then
check whether the front-
panelpower light is on or
off. If the power light is
off, check the power
supply. If the problem
persists, see "Contacting
Dell" in theSolutions
Guide for instructions on
obtaining technical
assistance.
Remove all cards. If
the computer still does
not start,
see "Contacting Dell"
in the Solutions
Guide for instructions
on obtaining technical
assistance.
Set the configuration
jumper to Maintenance
mode, and restart the
computer. Enter
thesystem setup
program and ensure that
the processor speed is
set correctly. Exit and
save the setting. Turn off
the computer, reset the
configuration jumper to
Normal mode, and then
restart the computer.
Remove all cards and
restart the computer to
determine if a resource
conflict exists. If a conflict
exists, resolve the
conflict.