Not long I upgraded to panther, I have had problems with all system software failing to launch. This includes mail, safari, address book, disk utility and software updater. It has happened to both G4s in my office. I erased the entire hard drive and reinstalled everything. For a few weeks this fixed the problem, then it returned, without me installing anything new that would have caused a new problem. Sporadically the programs would start working again, and then fail to launch on restart of the computer. PLEASE HELP!