Dell Optiplex GX520 Motherboard RJ291 + Intel Pentium D 3GHz CPU + 1GB RAM H8052 - The620Guy.com
OFFTEK 1GB Replacement Memory RAM Upgrade for Dell OptiPlex GX520 (DDR2-4200 - Non-ECC) Desktop Memory at Amazon.com
NeweggBusiness - DELL OptiPlex GX520 Desktop PC Pentium 4 3.0GHz 2GB 160GB HDD Capacity Windows XP Professional 32-bit 3 Years Warranty for School and Colleges only (Verification Required)
Dell L280P-01 - 280W Power Supply for Optiplex GX520 GX620 DT 745 755