Honeywell Bull:Laptop

Hey, Anybody familiar with the Zenith Data Systems line of Honeywell Bull laptop computers? I just recently got one from a friend, complete with an inkjet printer. I have pretty much all the specs/manuals that originally came with it. No software. I booted it up for the first time and got into the BIOS and fiddled with it enough for it to boot. It had DOS installed on it. Does anyone know if that is the original OS, if not what was it? Now here's the problem, when it boots now I can't get into BIOS or even into the system monitor program. I have tried boot disks, nothing. I can't get it to read the disk. hard disk or floppy. The boot disks I have tried have all been 1.44 mb, do you think that maybe a low density disk would make a difference, and if so does anyone know where I can get my hands on one? Anyone have any ideas? Sure could use some advice! Thanks, Mark Belles