Dell OptiPlex 755 User's Guide - Page 348

Light Pattern (continued) Problem Description Suggested Resolution A possible floppy drive or hard drive failure has Reseat all power and data cables. occurred. A possible USB failure has occurred. Reinstall all USB devices and check all cable connections. No memory modules are detected. Memory modules are detected, but a memory configuration or compatibility error has occurred. • If two or more memory modules are installed, remove the modules (see "Removing Memory" on page 316), then reinstall one module (see "Installing Memory" on page 314) and restart the computer. If the computer starts normally, continue to install additional memory modules (one at a time) until you have identified a faulty module or reinstalled all modules without error. • If available, install working memory of the same type into your computer (see "Installing Memory" on page 314). • If the problem persists, contact Dell (see "Contacting Dell" on page 370). • Ensure that no special requirements for memory module/connector placement exist (see "Memory" on page 313). • Ensure that the memory you are using is supported by your computer (see the "Specifications" section for your computer). • If the problem persists, contact Dell (see "Contacting Dell" on page 370). 348 Solving Problems