I just remembered the why of me having a 99 99 99 error
it was the 80 pin cable on a semi ata66 hdd.
some hdd's, post ata33 and not really done proerly up to ata100 drives, don't report their stats correctly to BIOS when the 80 pin cable is used.
also, an ata33 with an ata66 drive ont he same cable can show weird results.

putting the newer drive on an older system back onto a 40 pin cable fixed the 99 99 99 error.
and it was "d'oh, wish I'd thought of that 5 hours ago!" time