My PowerBook G4 suddenly froze, and when I restarted I found that I have only 512M of RAM now instead of 1G as I should. System Profiler says the lower DIMM slot is empty. One DIMM either became unseated or became bad. Unfortunately I don’t have the right tool to open it, so I’ll have to bring it to a dealer to have it fixed. Just one more thing in a frantic week.