Troubleshooting Tools 53
Troubleshooting Tools
Diagnostic Lights
  CAUTION: Before you begin any of the procedures in this section, follow the safety instructions in the 
Product Information Guide.
To help you troubleshoot a problem, your computer has four lights labeled "1," "2," "3," and "4" on 
the front panel (see "Front View of the Computer" on page 13). When the computer starts normally, 
the lights flash. If the computer malfunctions, the color and sequence of the lights identify the 
problem.
Light Pattern Problem Description Suggested Resolution
The computer is in a normal "off" 
condition, or a possible pre-BIOS 
failure has occurred.
The diagnostic lights are not lit 
after the computer successfully 
boots to the operating system.
Plug the computer into a working electrical 
outlet and press the power button. 
A possible processor failure has 
occurred.
Contact Dell (see "Contacting Dell" on 
page 126).
Memory modules are detected, 
but a memory failure has 
occurred.
• If you have two or more memory modules 
installed, remove the modules, reinstall 
one module (see "Installing Memory" on 
page 72), 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 "Installing Memory" on 
page 72).
• If the problem persists, contact Dell (see 
"Contacting Dell" on page 126
).