I've done something to my iMac and now have a problem opening some programmes. For example: When I try to open iTunes all I get is a warning saying "iTunes quit unexpectedly" with the option to reopen, but every time I select reopen it just brings up the same warning. Final Cut Express and iPhoto are also affected by the way. What have I done wrong, and how do I get things back to normal? I did re-install my OS X Snow Leopard and that enabled Safari to start again, but downloading itunes again did not help. Hope someone with MAC experience can help me sort out whatever it is I've done to screw up the imac. Thanks.