And while you are at it, Cajunmom, it might be well for you to burn a bootable CD. As you note, one of your machines doesn't have a floppy to allow emergency access.
Although you have a CD and a floppy that is not an indication that they are in the boot chain.
Can you get to the other machines' BIOS setup routine? Might be well to compare the entry procedures and stored values. It may well be that you could change one of the others to network first and nothing else to see if you get the same error message, possibly with the network disconnected.
I've done nothing with network boot so I'm not familiar with the error message. But on the one gateway I get a BIOS splash message from PXE that it hooking into the interrupt chain. I would be curious if your other machines do the same, and if it is different if the network is unplugged.
Is the failing machine on the network? And, if so, was the network stuff running before the system went down?
Ed Fair
Give the wrong symptoms, get the wrong solutions.