HG Monitor tests for the above problem showed my motherboard running very hot and very cold and it was suggested I come here to determine whether it is a sensor, my motherboard or the bios causing it. The original issue was solved satisfactorily.
Ran a Dell Support Assist test on motherboard and it passed. Don't know what value it has.
The HG Monitor report attached was run first thing in the morning.
Dell Inspiron 530, build 2008, 2009 Bios, Windows 7-32bit