How old is the machine? Almost 20 years old? I will have to assume that against all odds you still have the original mother board with a ISA IO board plugged into it. The ribbon cable goes from that board to the HDD and another ribbon cable goes to the floppy.
I would be looking through thrift stores, Ebay, and newegg,com for a replacement. Also try cleaning the edge connector and plugging it back in.
George
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)