When I woke my MacBook this morning, it was frozen. The screen came on, but it didn't respond to keyboard, touchpad. I forced a shut down by holding the power button. Is there a log file or set of diagnostics I can use to determine what was happening before it froze?
You might be able to find the root cause of the freeze in the Console application. You can find it in /Applications/Utilities.
Take a look at the system.log on the left-hand side and scroll through the entries to a time when the freeze occurred.
Hopefully you find something that points you in the right direction.