Well, I gave it a try.
Bought the case and motherboard, 1 gig of ram and a Celeron D processor. It powers up, I see a "Pentium 4" logo but the floppy disk does not start up or even show a indicator light and the keyboard is not working. I have the option to tab or del but nothing happens.
So either my old keyboard is bad (possible) and thus the computer won't start up any further (?) or I got a little over my head. :-(