Every once in a while my MBP (running Leopard) just freezes. I'm relatively new to mac and was wondering what I can do short of cold-booting it. I know Cmd+Alt+Esc. But for instance when the screen displays just my background, no dock, no menu bar and Cmd+Alt+Esc doesn't seem to do anything are there any other keyboard combinations I should try before holding down the power button? Or are there other things I should do? I rarely have a problem that so thoroughly crashes my system, but when I do I'm stuck realizing that while I knew a number of things to try in Windows (and often, often had to try them) I really don't know what to do when Mac doesn't just work.