For no reason I can figure out, Safari stopped working a few weeks ago.  I get this error message: "Safari cannot be opened because of a problem. Check with the developer to make sure Sarai works with this version of Mac OS X.  You may need to reinstall the application.  Be sure to install any available updates for the application and Mac OS X."   I did do all the updates.  Am running OS 10.7.5.   I tried to start my machine from Recovery but since I'm using a...