With a flash of genius (desperation?) I noticed this am that my M/board (EPOX 8KTA3) had a pair of UIDE connectors as well as 2 IDE conns), to which I gradually transferred the drives, and MIRACLE I am back running again on the desktop.
Thanks to all who have, as usual, helped me here, and a final Q for you all, since the problem may stem from a fault in the 2 IDEs, is there a way I can check the serviceability of these?