i own a powerbookTi 15 in, 1 Ghz, 512 RAM. i get this problem where the screen gets messed up, and these horizontal lines start appearing everywhere, making it impossible to use. if i can i'll try to take a screen shot. i don't know what causes it. this has happened two times in the past, and what i did was install panther all over again, plus download all the updates again and do those too. it seems to fix it, but it's back now. the whole process is a pain and took up half my day, and i was wondering if anyone knows what the issue is. should i call apple and send it to them to fix it? does anyone know what's going on?