If you have a video card and hard drive but want a pretty nasty computer here is one

COOLER MASTER RC-690-KKN1-GP Black SECC/ ABS ATX Mid Tower Computer Case - Retail $69.99
COOLER MASTER RS-600-AMBA-D3 600W ATX12V V2.3 SLI Certified CrossFire Ready 80 PLUS Certified Modular Active PFC Power Supply - Retail $79.99
Intel Core 2 Duo E8400 Wolfdale 3.0GHz LGA 775 65W Dual-Core Processor Model BX80570E8400 - Retail $159.99
ASUS P5Q Pro Turbo LGA 775 Intel P45 ATX Intel Motherboard - Retail $134.99
G.SKILL 4GB (2 x 2GB) 240-Pin DDR2 SDRAM DDR2 1066 (PC2 8500) Dual Channel Kit Desktop Memory Model F2-8500CL5D-4GBPK - Retail

With combo deals and instant savings it comes to $439.99 with free shipping.