Ultimate Boot CD

Hi:
I am trying to resurrect an old (1996) Gateway in order to donate it to some group that can use it. However, I am stuck with the "Invalid system disk" message no matter what I try to boot with. This includes UBCD, Boot Disk, WXp, W2k pro, W98(2) and W95. So, I have tried CDROM and floppy boots. The harddisk I am using was reformatted as one partition (FAT32) on another computer using Partition Magic.
The BIOS settings look ok...all components are installed and look correct. If I boot with only UBCD inserted, it sounds as if the drive is being activated (read?) for a few seconds before the failure
message appears.

I think my problems are unrelated to UBCD, but I was hoping someone could suggest a cause/fix.

Thanks.

Hmm maybe both the floppy and cdrom drives are defective, so you always end trying to boot on the HDD, which has no system ...

The current CD drive was working in the very recent past. I did try another drive and cable with no change.

I was also thinking of temporarily trying the floppy from my working computer, but I haven't tried this yet.

There could be a problem with the motherboard, but I don't know if I want to go to a replacement there.