Buy the Dell OptiPlex GX520 SFF Dual Core 1GB DVD Desktop PC...
Dell Optiplex GX520 Desktop PC
How to change / Upgrade / Install / Remove a Processor / CPU in a Dell Optiplex GX520 GX620 - YouTube
Refurbished: Dell Optiplex GX520 Small Form Factor - 2.5GHz Intel Celeron Processor - 2GB Memory - Windows 7 Home Premium (1 Year Warranty) - Newegg.com
How to change / Upgrade / Install / Remove a Processor / CPU in a Dell Optiplex GX520 GX620 - YouTube
DELL Cc079 Processor Heatsink For Optiplex Gx520 620 | eBay
Refurbished: Dell Optiplex GX520 Small Form Factor - 2.5GHz Intel Celeron Processor - 2GB Memory - Windows 7 Home Premium (1 Year Warranty) - Newegg.com