OptiPlex 990 Small Form Factor (SFF) Removal Guide for the Heatsink, Intrusion Switch, IO Panel, Internal Speaker and Power Supply | Dell US
Restored Dell Optiplex 990-SFF WA1-0430 Desktop PC with Intel Core i7-2600 Processor, 16GB Memory, 2TB Hard Drive and Windows 10 Pro (Monitor Not Included) (Refurbished) - Walmart.com
Dell Optiplex 990 SFF – RefurbIT
Amazon.com: Dell Optiplex 990 SFF Desktop - Intel Core i5 3.1GHz., 16GB DDR3, 1TB Hard Drive, Windows 10 Pro 64-Bit, WiFi, DVD-ROM : Electronics
OptiPlex 990 Service Manual (Ultra Small Form Factor)
OptiPlex 990 Small Form Factor (SFF) Removal Guide for the System Cover, Front Bezel, Optical Drive, Drive Cage and Hard Drive | Dell US
Optiplex 990 may freeze with a blinking cursor during startup | Dell US
OptiPlex 990 Ultra Small Form Factor (USFF) Removal Guide for the Wireless Module, Internal Antenna, System Fan, Memory and Heatsink | Dell US
Dell Optiplex 990 PC SFF Desktop i5-2400 3 1GHz 4GB Ram 500GB HDD Win10 Pro