Out of the blue: programs like Photoshop and Word wouldn't open but started asking for new setup. When I tried to restart iMac, I got this warning: "the startup disk no longer has a valid system folder. System and finder must be in the system folder. If you continue, you may not be able to restart the computer." OK, well, system & finder ARE both in the folder. All my files are backed up and I am ready to reinitialize if this will fix the problem (though I have OS10 also, some of my fav programs are in old version and I can't replace them yet). But I am concerned that the computer will just k e e l o v e r a n d d i e. Any ideas please? Tx, Clare in IB, CA