100 Troubleshooting Tools– Ensure that the processor power cable is securely connected to thesystem board (see "System Board Components" on page 148).• If the power light is steady amber, a device may be malfunctioning orincorrectly installed.– Remove and then reinstall the memory modules (see "Memory" onpage 157).– Remove and then reinstall any cards (see "Cards" on page 162).• Eliminate interference. Some possible causes of interference are:– Power, keyboard, and mouse extension cables– Too many devices on a power strip– Multiple power strips connected to the same electrical outletDiagnostic LightsCAUTION: Before you begin any of the procedures in this section, follow thesafety instructions in the Product Information Guide.To help troubleshoot a problem, your computer has four lights labeled 1, 2, 3,and 4 on the front panel (see "Front View (Tower Orientation)" on page 21 or"Front View (Desktop Orientation)" on page 25). When the computer startsnormally, the lights flash, and then turn off. If the computer malfunctions,use the sequence of the lights to help identify the problem.NOTE: After the computer completes POST, all four lights turn off before booting tothe operating system.Diagnostic Light Codes During POSTLight Pattern Problem Description Suggested ResolutionThe computer is in anormal off conditionor a possible pre-BIOSfailure has occurred.Plug the computer into a workingelectrical outlet and press the powerbutton.
