We could probably use a bit more detail. Presumably, the computer is powering-on; do you get any screen prompts? Do the floppy drives sound like they are trying to spin? How long since this machine last booted from a floppy disk correctly?

I have this note on my Linux Mint system that I've used to install packages on an offline machine. It requires that you have a working system with the same LM version and the same bit architecture (not relevant with LM 20, as that's 64-bit only) connected to the internet. In synaptic you can select …