Specifications:
http://h20564.www2.hp.com/hpsc/doc/public/display?docId=emr_na-c01926347
Technical Reference Guides:
http://h10032.www1.hp.com/ctg/Manual/c01960471.pdf
Illustrated Parts & Service Map: HP Compaq 8000 Elite Ultra Slim Desktop Business PC
Hardware Reference Guide HP Compaq 8000 Elite Ultra-Slim Desktop PC
Buy for $80
http://www.sears.com/hp-compaq-8000-elite-usff-desktop-core2duo/p-SPM9362761517
Buy for $150
http://www.newegg.com/Product/Product.aspx?Item=9SIA5YV20K0343#close
Buy for $60 (no hard drive or caddy)
HP Compaq 8000 Elite Ultra Slim Desktop E8400 3 0GHz 4GB DDR3 No HDD Caddy | eBay
Video teardown: