Dell OptiPlex 980 (Early 2010) - Manual (Page 24)

failure has
occurred.
one until you find the bad one.
Power connector
not installed
properly.
Reseat the 2x2 power connector from the power supply unit.
Possible
peripheral card
or system board
failure has
occurred.
Remove all peripheral cards from the PCI and PCI-E slots and restart the
computer. If the computer boots, add the peripheral cards back one by
one until you find the bad one.
A possible
system board
failure has
occurred.
Disconnect all internal and external peripherals, and restart the computer.
If the computer boots, add the peripheral cards back one by one until you
find the bad one.
If the problem persists, the system board is probably bad.
A possible coin
cell battery
failure has
occurred.
Remove the coin cell battery for one minute, reinstall the battery, and
restart.
The computer is
in a normal on
condition.
The diagnostic
lights are not lit
after the
computer
successfully
boots to the
operating
system.
Ensure that the display is connected and powered on.
A possible
processor failure
has occurred.
Reseat the processor.
Memory modules
are detected, but
a memory failure
has occurred.
If two or more memory modules are installed, remove the modules (see
your service manual), then reinstall one module (see your service manual
and restart the computer. If the computer starts normally, continue to
install additional memory modules (one at a time) until you have identified
a faulty module or reinstalled all modules without error.
If available, install working memory of the same type into your computer.
A possible
graphics card
failure has
occurred.
Reseat any installed graphics cards.
If available, install a working graphics card into your computer.
A possible floppy
drive or hard
drive failure has
occurred.
Reseat all power and data cables.
A possible USB
failure has
occurred.
Reinstall all USB devices and check all cable connections.
No memory
modules are
detected.
If two or more memory modules are installed, remove the modules (see
your service manual), then reinstall one module (see your service
manual) and restart the computer. If the computer starts normally,
continue to install additional memory modules (one at a time) until you
have identified a faulty module or reinstalled all modules without error.
If available, install working memory of the same type into your computer.
Memory modules
are detected, but
a memory
Ensure that no special requirements for memory module/connector
placement exist.