Applications "unexpectedly Quit" Messages


i have a G4 powerbook with OS X ver 10.2.8. i have made no recent upgrades or downloads. now i am unable to open many applications, including safari, internet explorer, adobe reader 6.0. when i try i get an immediate "the application safari (etc.) has unexpectedly quit. the system and other applications have not been affected." other applications i am able to work in for a while, like ms word, but eventually will get kicked out with the same message. sometimes the whole computer will freeze up, and all i can do is reset it with the power button. i am unable to get on the web to download any "purging" software because no browsers will open. i've tried deleting preference lists for safari and others, and ran repair permissions in disk utility. those did nothing.