i just woke up my dual 867 from sleeping for a couple of hours and i got a screen i have never ever ever seen on a mac. it was black, with a little box in the middle that had a picture of the power button and said "you need to restart your computer, etc. etc. (how to restart it)" and it had it in a couple of different languages. what the hell is going on?? i've never seen this, does anyone know why it happened and i how i can keep it from happening again?