I've unplugged the WDC unit and PC appears to be operating good. It also appears to be operating somewhat faster. I'll now get a new WDC unit.
I'd just like to say a very big thankyou once again for all your excellent help & advice. It's very reassuring that there are commited people out there willing to extend a helping hand and share their knowledge.
What more can I say...geeks to go are exceptional people and highly recommended.
Thanks , cheers and all the very best...