Dell OptiPlex 390 (Mid 2011) - Manual (Page 72)

• If available, install working memory of the same type
into your computer.
LED
Power Button
Problem Description A possible hard drive failure has occurred.
Troubleshooting Steps Re-seat all power and data cables.
LED
Power Button
Problem Description A possible USB failure has occurred.
Troubleshooting Steps Re-install all USB devices and check all cable
connections.
LED
Power Button
Problem Description No memory modules are detected.
Troubleshooting
Steps
• 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.
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