i found this dell optiplex 755 in a scrap yard perfectly functioning{came with side panel just have it off} its ungodly slow with only a single stick of ddr2 2gb ram and
PU052-U | Dell System Board (Motherboard) for OptiPlex 755 (Refurbished)
Refurbished: Dell Optiplex 755 A Grade Desktop PC with Intel Core 2 Duo 2.66GHz, 4GB RAM, 1TB HDD, DVDRW, Windows 7 Professional 64 Bit, Microsoft Authorized Recertified Desktop PC w/1 Year Warranty - Newegg.ca
Dell Optiplex 755 SFF - Intel Core 2 Duo 2,4 GHz - 4 Go de RAM - 1 To HDD - Win7 - WiFi - DVD-ROM - Remis à neuf | Walmart Canada
Dell Optiplex 755 Desktop computer Fast Core 2 Duo 2.93GH windows 7 - CNC - WIFI | eBay