HH drives

Hi All I have a newbie question <collective groan from list> I don't have much experience with HH type drives and recently unearthed a Wyse Technologies machine at the local refuse recycling centre (it's a shop rather than me wading though a landfill site - I'm not that desperate). Inside this machine (stated built in 1986) were two HH type 5.25" hard drives (one a Segate ST-251 the other not branded but built 1989). On boot up I get: Pheonix 80386 ROM BIOS version 3.53 (c) 1985, 1986 Pheonix Technologies Ltd 640K Base 1408K Extended Memory Hard Disk Failure I have booted the system using a floppy and one drive (the unbranded one) is partially readable. It is a 41Mb drive split into two partitions (primary & extended) - FAT16 system It seems to have been installed with DRDOS. Using my later versions of DOS on floppy I cannot get the drive to respond to any standard commands (I always get a 'Sector not found' error). Can anything be done to revive these disks or were they left unparked and now physically damaged? I have another 5.25" hard drive displaying the same unresponsive characteristics... are they all dead?

Thanks in advance Alan