He is talking about Pentium 1 MMX most probably 200 Mhz and mobo maybe 440zx.
like mayur said u can use the seagate utility which afaik work only for seagate drives. But I have a more simple soln. Try it , maybe it will help u.
I had a P1 200 Mhz, attached 20 GB hdd, it recognized only 8.4 GB. Got my new system (P4 HT 2.8, 865, 40 GB, Win Xp pro), attached the old 20 GB to my new rig, formatted the unallocated space (ie the remaining 11.6 GB) into 2 partitions using Xp's Disk Management, then again connected it to my old rig and it worked , it recognised all the partitions. I cud store/delete anything on the new partition. It worked for me. Maybe it was a miracle . Try it.