Dell D490 manual That your computer is successfully

Light Pattern	Problem Description	Suggested Resolution
	No memory modules are detected.	1 Reseat the memory modules to ensure
		that your computer is successfully
		communicating with the memory.

2 Restart the computer.

3 If the problem still exists, remove all the memory modules and install one memory module in memory module connector DIMM_1.

4 Restart the computer.

A message appears stating that because your memory is not paired, the system will operate with reduced performance and reduced error- correction capability

5 Press <F1> to boot to the operating system.

6 Run the Dell Diagnostics. See your User’s Guide for more information.

7 If the memory module passes, shut down the computer, remove the memory module, and then repeat the process with the remaining memory modules until a memory error occurs during start-up or diagnostic testing. If the first memory module tested is defective, repeat the process with the remaining modules to ensure that the remaining modules are not defective.

8 When the defective memory module is identified, contact Dell for a replacement.

Quick Reference Guide

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