when you click on it what happens? Did it work yesterday?
Provide exact system info, what files you are trying to open using what method, where they are stored and all that.
Ok here goes, computer is a macbook pro OSX 10.7.5. Adobe premium package and in this instance version 12.1 x 64. I can open the photoshop program but that is as far as it goes. l have tried opening jpeg, gif, ai, psd, cant open any of them. And yes, it worked yesterday and every other day lve used it for the past 18ish months. When l click on 'open file', nothing happens.