floppy will not read boot disk.

I am trying to use a boot disk to set up a computer but I keep getting the error-“Invalid System disk, replace disk and press any key.” There is nothing wrong with the disk, I have made several of them and they work on other computers but this one. I have replaced the the floppy drive, the cable, disabled the on board controler and replaced it with a ISA FDC board. I did each of these at least twice each. I am stumped. I have played around with many settings in the bios setup also. Any ideas?
thanks