Hi. I only tried one Powerpoint presentation. On Mac it saves as a 'pptx file, which doesn't play in windows. It said something like it wasn't recognised. Someone else says I need I-Work to do it properly. I'm not that computer literate, and as you can see by the time lapses of my entries, I don't have the time to devote to it. I'm really disappointed, because other Mac users swear by Apple, but it's all a bit bewildering to me. I think I'll have to sign up to a tutorial. I CAN go back to the Apple shop for some 1 to 1, but I haven't got around to it yet. It's 30 miles away, and I work, so it's tricky. I had no problems with the windows PC when I bought it first - the instructions were crystal clear. I don't know about the ones for the Mac - I find them rather obscure. I have a friend who used keynote, and that didn't play in windows either. She had to redo the whole thing on the windows pc.