I just installed all of my "software updates" and also installed Adium (IM program) and evil Internet Explorer on my PowerBook G4--now, several applications refuse to open, such as Calculator, Quick Time Player, Mail, iPhoto, iMovie, Garage Band, Acquisition, and LimeWire. Additionally, MacHelp won't open, even if I use command-? instead of the drop-down menu. There must be a conflict somewhere--please help!