Dell Dimension U7021 Owner's Manual page 54

Light Pattern
A B C D
A B C D
A B C D
A B C D
= yellow
= green
= off
54
Advanced Troubleshooting
Problem Description
Memory modules are detected, but a
memory failure has occurred.
A possible graphics card failure has
occurred.
A possible floppy or hard drive failure
has occurred.
A possible USB failure has occurred.
Suggested Resolution
• If you have two or more memory
modules installed, remove the
modules, reinstall one module (see
page 77), and then restart the
computer. If the computer starts
normally, reinstall an additional
module. Continue until you have
identified a faulty module or
reinstalled all modules without error.
• If available, install properly working
memory of the same type into your
computer (see page 77).
• If the problem persists, contact Dell
(see page 131).
• If the computer has a graphics card,
remove the card (see page 87),
reinstall it, and then restart the
computer.
• If the problem still exists, install a
graphics card that you know works and
restart the computer.
• If the problem persists or the
computer has integrated graphics,
contact Dell (see page 131).
Reseat all power and data cables and
restart the computer.
Reinstall all USB devices, check cable
connections, and then restart the
computer.