OK - penny dropped. My ctl3d32.dll had been replaced by some clunkly old copy dating back to '95. Suspect some freebie useless Corel app. that I put in just before Xmas. Found a good one dated 23/04/99 and replaced it.
All well and back running properly. Thanks fellers (and PPRuNe) for giving me the hint I needed.
Have a good '02.