I bumped into this same mainboard, 15 units, actually.
They come out of an HP Pavillion zd8080us Notebook PC. They are indeed Socket 775, housing (standard desktop) Pentium 4s. These units have three base fans and a huge heat sink. Strange machine, fairly large board.
I found the Maintenance and Service Guide here
http://support.hp.com/us-en/product/HP-Pavilion-zd8000-Notebook-PC-series/434660/model/441758/manuals?cc=us&lang=en,
and the specs at PCWorld
http://www.pcworld.com/product/1331683/hp-pavilion-zd8080us-notebook.htmlSee photos...
Attachment:
File comment: Mainboard out of the base
MainAndBase.JPG [ 503.95 KiB | Viewed 6648 times ]
Attachment:
File comment: The Mainboard in the base
HPzd8080usMain.JPG [ 490.54 KiB | Viewed 6648 times ]
I cleaned the metal from the reader slots, and have since pulled the cover plate and the latching bar from the socket assembly, in hopes of a better price.