last night i was doing normal things on my laptop; browsing the internet, checking mail, listening to music. all of a sudden, my screen froze up with lines across it. i let it sit for a minute to see if it'd unfreeze, but it didn't. i held the power button to shut it down. when i tried to reboot it, this error message popped up telling me i need to restart my computer. i restarted it. same message. shutdown. same message. tried resetting the PRAM. same message. tried some trick with removing the battery. same message. so WTF is wrong? please tell me my computer isn't fubar'd. it's not even two years old. my ibook lasted me for nearly 5!