OK Maybe this question has been asked before but can you please give a small and quick answer? Is it possible to store applications on external HDDs? What happens when the HDD is not connected? e.g if a particular file format opens using Photoshop only and my Photoshop program is on an external HDD and I disconnect my HDD before starting up the Mac then what happens when I try to open the file? On Windows it goes searching for the program which opens it and messes up the registry and there are fireworks under the hood. Can I connect the HDD on another Mac and expect the apps to run like normal? What about the preferences? I am sure this i snot possible on Windows without problems but what about Mac? This can become another reason for me to tell my friends to get a Mac.