Its me yet again.
Just a follow up on progress.
Having tested the above fix on my laptop evertything was great. On trying the fix on my mate's machine no luck - still got the half screen thing
So in a way of proving what it was, I tried the fix on my desktop PC - no luck.
I have, howeveer, noticed that my mate's PC and my desktop PC both have ATI Radeon cards in them (not the same model), but my laptop has a Nvidia GeForce card in it.
So the graphics card may be causing the problem (or at least stopping the fix from working). I am going to ask my PC dealer to lend me a GeForce card for testing and I will post how I go on.
All the best
Mark