I'd recommend just using a linux boot CD - you could download
knoppix , which is a featureful, bootable linux CD that runs a whole system - this would let you mount your old hard drive, fix the master boot record, mess with configuration files, or whatever it is you need to do to fix it.
Also, often your original linux install CD doubles as a rescue disk.
If you really want to get a rescue floppy, I'd search for a floppy disk image of one online, then you can download a program for windows that will let you use the disk image to make a bootable floppy disk.