My girlfriend has a MacBook Pro and it has worked great, until today. The Mac OS X on the system has suddenly frozen her out of everything but the finder and the desktop. It boots fine and pops up on the desktop, and everything looks completely normal. But when you want to run an application and click on it, a big fat question mark appears over the icon in the bottom menu, no matter what application you click on. Further more it appears that all applications has been wiped from the system when you enter the applications folder. It is completely empty. Now I've tried to click on different stuff, such as the internet, to turn it off, but nothing happens. I've also tried to enter the OSX preferences, but nothing happens when I do. At times it comes up with the message that you don't have permission to open certain programs, even though the programs apparently dont exist on the Mac. I've interrogated my girlfriend about her activity, and she swears she has done nothing out of the ordinary like download shady software or anything, and apparently all of this has come like lightning from a clear sky. I hope somebody can help us out, cause I'm at my wits end about what to do.