Refurbished: Dell OptiPlex 780 USFF Desktop Intel Core 2 Duo E8400 3.0GHz 4GB DDR3 RAM 250 GB HD DVD-RW WiFi Bluetooth Microsoft Windows 7 - Newegg.com
NeweggBusiness - Dell Optiplex 780 SFF Core 2 Duo E8400 3.0GHz 4GB 160GB Win 7 Pro
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Refurbished Dell 780 SFF Desktop PC with Intel Core 2 Duo E8400 Processor, 8GB Memory, 17" LCD Monitor, 1TB Hard Drive and Windows 10 Pro (D780C2D8G1TBW10PRO17)
OptiPlex 780 Small Form Factor (SFF) Removal guide for the Cover, Optical Drive, Memory, Hard Drive and the Power Supply | Dell US
Amazon.com : Dell OptiPlex 780 SFF Desktop Computer - Core 2 Duo 2.93GHz 2GB Windows 7 Pro : Electronics