Old mother boards have many problems and this is one of the related problem to my collegue.The pc shows pri slave no installed.I tried several ways to connect remove etc but finally i came to know that the jumper of hard drive was missing.I placed a jumper and the hard drive was showing in bios.
however most in cases if the hard drive is defective or a new one or might formatted on 98 version and fixed to someother version it shows not installed in bios.so i refer to check before repairing .
i am posting images because most of them dont know what is jumper.I too even thought that the mother board jumper instead of hard drive jumper.
If you are facing the poblem from bios not detecting then first check jumper and then th ribbon of hard drive if both were are good then chech the mother board with another hard drive.so this steps will findout whats the problem.even most motherboards dont detect hard drives properly.some motherboards needs to enter values in bios so you should copy fro hdd label and type them in bios user settings.
If you have any problem feel free to post below.i will try to answer them as much as i can