My brother has been having with his Powerbook freezing for the last few weeks. He just got home from college and I experienced the same problem. Just a few minutes ago I tried restarting and it refused to start back up. I can access all the data easily with target disk mode so I think the hard drive is fine. Could it be the ram? Here is a picture of the message that shows up when I try to start it. Any help would be appreciated, and we are taking it to the Apple store first thing tomorrow. Thanks.