Hi,this will probably be a stupid question for most of you but I've just made the switch from Pc's to an Intle iMac.For the most part I'm more than impressed but I'm having a few problems when it comes to installing 3rd party software,I keep getting a window pop up say that I haven't selected a 'Default App'...How do I do this and how do I know which App to use to open programs.Thanks,Andy.