There's a couple of things it could be.  
For one, your bios could have dumped its configs because of some fault, or just because the battery died.  
 
So is this error comming up immedietly and you aren't seeing the prompt to get into the bios?  If not, do you happen to be using a USB keyboard.  By default, a lot of older bios settings have usb keyboard support disabled.  So you can try connecting a PS/2 keyboard and that should allow you back in to disable the floppy again.
 
If it continues to happen even after that then your battery on the motherboard is probably dead.  You can look at it and see the model number and purchase a new one.  Its about the size of a quarter and normally silver.
 
Last, it could possibly be some other component dragging you down.  If you have multiple memory sticks try removing one then the other to see if that lets you move forward.   From there, try disconnected cdrom, extra pci cards (modem, network cards, etc), hard drives, and externally connected devices such as mouse, thumb drives(I've seen systems hang when a thumb drive is left connected on boot)
 
So go from there and if that doesn't resolve your problems let us know.