1) Yes, I would format the drive because you have no idea what was on there, it could even have an old and previously undiagnosed infection for all you know. Plus its better for the security and privacy of the original owner. If you want to salvage the drivers first then go ahead, but I would give them a good AV scan on a known good machine before trying to re-install them.

2) Disk 1 of 4? MS-DOS 6.22 came on 3 disks, not 4. Maybe you are trying to boot from the enhanced tools disk my mistake. Try booting off one of the other DOS disks.

3) Odd, but if you see the floppy drive kick when you power up I would assume that its trying to boot from the floppy drive first (seeking boot disk). The non system disk error you were getting at boot would indicate that this is the case.

Yes. Ok. DOS 3pcs disks and +1pc enchanced disk.
- I'll see if I mixed the disks.

The bios is AMI 1991. (Wonder if it then automatically boots from floppy A:\ if the disk is inserted at startup.)
It looks something like this. Photo.

So I just put the disk#1/3 in at the startup and the setup should pop up ?

Kudos to you for actually reproducing the BIOS screen on Paint rather than snapping a photo with our phone; you got a good chuckle out of me when I was least expecting one.

Under advanced CMOS setup you can set the boot priority no?

In WinImage when writing the backup floppy disks:
- What parameters do I need to set to WinImage for 1.44MB boot-disks to work with 1991-92 computers ?
Here it says I must change: "File System to Fat 12⁄16" ?
http://www.josephspurrier.com/book-disk-creation-guide/

It must have been a simple corrupted data file or such if default parameters are ok to go with.
- What other WinImage alternatives are there ?

"Under advanced CMOS setup you can set the boot priority no?"
- I will try that option.

When Dos disk A:\ #1/3 is inserted at start up it says:
"Non-system disk or disk error replace and strike any key when ready"
It is either:
1.) 1.44MB Floppy disk data is corrupted.
2.) Or the 1991 computer's BIOS doesn't boot from the A:\ floppy.

user33331 wrote:

In WinImage when writing the backup floppy disks: - What parameters do I need to set to WinImage for boot-disks to work with 199 […]
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In WinImage when writing the backup floppy disks:
- What parameters do I need to set to WinImage for boot-disks to work with 1991-92 computers ?
Here it says I must change: "File System to Fat 12⁄16" ?
http://www.josephspurrier.com/book-disk-creation-guide/

It must have been a simple corrupted data file or such if default parameters are ok to go with.
- What other WinImage alternatives are there ?

WinImage should 100% work, you don't need to do anything special. A floppy image is a literal copy of every bit on the disk, including the file system and boot sector and everything. There are no settings in WinImage to worry about, and WinImage is the perfect software to do what you're trying to do. If it still doesn't work, then in order of likelihood:

1) your floppy disk is bad (this is very likely, 1.44" floppies are notoriously unreliable... Even if it's new, or new old stock, it cannot be trusted)
2) your floppy drive or data cable is broken/installed wrong
3) your motherboard is misconfigured/broken

There are no systems from this era that will not boot from floppies, and usually A: is always the first boot priority by default. There should indeed be something in the BIOS that says "boot order A,C". If it says "C,A" then change it.

Try a known good floppy disk on the system itself, do SYS A:, and boot from that. If that works you know the CMOS setup and floppy drive/motherboard are all OK.

https://www.allbootdisks.com/download/iso.html

have you tried a dos boot disk from here ? It's not the original setup, but you can also try these.
if they don't work, you either do not have a bootsector on the disk or your boot order is just wrong 😉