Boot from CD w/outboard USB CD drive?

Ol' "Build 1" seems to have freaked out, won't boot in any mode. Tried the CMOS jumper, even pulling the battery, etc... but no joy. Last time this happened I was a able to boot from the XP disc and do a repair install, but it's not working this time. I'm wondering if it's because I've been using an external drive that connects via USB...? I can try pulling the CD drive from Build 2, but trying to get more info first.
No floppy drive in this machine either, never did make a recovery floppy, so that's not an option. Any thoughts?
No floppy drive in this machine either, never did make a recovery floppy, so that's not an option. Any thoughts?