Dell OptiPlex 990 (Early 2011) - Manual (Page 69)

• If the problem persists, the system board is faulty.
LED
Power Button
Problem Description A possible coin cell battery failure has occurred.
Troubleshooting Steps Remove the coin cell battery for one minute, reinstall
the battery, and restart.
LED
Power Button
Problem Description A possible processor failure has occurred.
Troubleshooting Steps Re-seat the processor.
LED
Power Button
Problem Description Memory modules are detected, but a memory failure has
occurred.
Troubleshooting
Steps
• If two or more memory modules are installed,
remove the modules, then re-install one module and
re-start 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.
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