Thank you all for your input, it has been most helpful.
The system isn't up yet, but I called in an army of techs and they are crawling over it this morning. As it happens, you analysis was dead on- I am waiting to see if it was a hardware failure or simply a matter of the boot drive maintenance being negleted for ohh....three years.....and the disk being so full as to prohibit proper start up.
Obviously I am not an IT person, we're just a little company (who was about to upgrade our entire network, as it happens---I think the computer gods took a hand).
I'll update you all when I get more inof.
Thanks so much!