Dell OptiPlex 990 Desktop Service Manual page 78

LED
Power Button
Problem Description
Troubleshooting Steps
LED
Power Button
Problem Description
Troubleshooting Steps
LED
Power Button
Problem Description
Troubleshooting
Steps
78
– If available, install working memory of the same type
into your computer.
A possible hard drive failure has occurred.
Re-seat all power and data cables.
A possible USB failure has occurred.
Re-install all USB devices and check all cable connections.
No memory modules are detected.
– If two or more memory modules are installed, remove
the modules, then reinstall one module 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.