Dell OptiPlex 990 (Early 2011) - Manual (Page 67)

LED
Power Button
Problem
Description
Memory modules are detected, but a memory power
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. If only one
memory module is installed, try moving it to a different
DIMM connector and re-start the computer.
• If available, install verified working memory of the
same type into your computer.
LED
Power Button
Problem Description BIOS may be corrupt or missing.
Troubleshooting Steps The computer hardware is operating normally but the
BIOS may be corrupt or missing.
LED
Power Button
Problem Description A possible system board failure has occurred.
Troubleshooting
Steps
Remove all peripheral cards from the PCI and PCI-E
slots and re-start the computer. If the computer boots,
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