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 …