Well I really think I am goibg dippy. On my screen the shadows are very pronounced. On the desktop the shadow against the dark blue is pale whereas against the light blue section in is dark. Against a black background, my pictire viewer for example it is almost white but even putting a snippet file onto a memory stick and putting that in my other XP machine I can't see the shadow. It must be something specific in the monitor though if i take a screenshot one would think that would reproduce on another complaetely independent PC.
Will investigate the monitor later. Haven't tried switching the monitor so will try that first when i return from dog walking. wiil report back later!