Use your emergancy backup startup floppy to boot, or borrow one from someone running the same OS who's made one.
If bootup is not seeking floppy before hard drive, you need to hit whatever key gets you into boot options and set floppy as first option, then boot with startup floppy in the drive.
If you can get deep enuf into the boot that you have options on loading the operating system, hit the right key (Del, f8 whatever) and try loading the OS in safe mode.
Sounds like you might need to reflash the bios, if so, check your manual on how this is done.
Good luck