Thank you very much for your answer. I'll try out your instructions now. I was hooping not to be charged as I took out a 3 year AppleCare Protection Plan when I bought my MacBook last year. Is there anything that you can do about this?
Richard, Sorry, I hadn't realised that you are a paid service and that I've only paid the deposit. So I'm very happy to pay you!
I've tried to follow your advice and have pressed Command - Shift - 4 which produces a small circle with cross-hairs. I can move this round the Bing map screen but I can't select an area. When I press the track-pad the circle and cross-hairs just disappear. Please help!