How to Install, Replace, Upgrade or Change the CPU in your DELL Optiplex - 755 SFF - YouTube
Used Dell OptiPlex 755 Tower Desktop PC with Intel Core 2 Duo Processor, 16GB Memory, 512SSD Hard Drive and Windows 7 Pro (Monitor Not Included) - Walmart.com
Dell Optiplex 755 (Intel Core 2 Duo 2.40GHz 1GB 80GB Win 7) Desktop PC | eBay
Dell Optiplex 755 Sub-Compact Computer; base (CMPUDL755SBB)