Tried that,
Enabled the BIOS, set things to send 'start'
Confirmed that it sees the drive - but still will not boot.
It looks like the motherboard BIOS is too old for the application [will not take 16383 cyl hard drive]
Time to raid a friend's junk pile for a not quite so old ATX box [and put the SCSI disks [all 5 gig worth] back into this one]