Dell Precision D490 Quick Reference Manual page 38

Light Pattern Problem Description
A possible graphics card failure has
occurred.
A possible floppy or hard drive failure
has occurred.
A possible USB failure has occurred.
38
Quick Reference Guide
Suggested Resolution
1
If the computer has a graphics card,
remove the card, reinstall it, and then
restart the computer.
2
If the problem still exists, install a
graphics card that you know works and
restart the computer.
3
If the problem persists or the
computer has integrated graphics,
contact Dell.
Reseat all power and data cables and
restart the computer.
Reinstall all USB devices, check cable
connections, and then restart the
computer.