Suddenly many things are wrong with my iBook G4 running Leopard. There is a white box over the right-hand side of my menubar, and Spotlight, Airport, clock, and all my startup items (Quicksilver, WeatherDock, MenuCalendarClock) are gone. I can't open many applications that might help (including Disk Utility, Finder Help, System Preferences). I cannot open Mail, but I am indeed online as I can open Firefox and Fetch and use them. I tried inserting the Leopard Disk and reinstalling, but I can't run the install program. I repaired permissions in single user mode (startup with Command-S, run fsck) and my hard drive seems to be fine. I plugged in my backup drive and tried to restore from Time Machine. I get the Time Machine interface, but I can't click on any past backup windows. When I place the mouse cursor over the white rectangle on the menubar, I get the beach ball. I am unable to shut down or logout without doing a hard restart. I can't get to System Preferences to create a new user to see if it's particular to my login. Please help. I know Leopard requires more memory than I have, but I have been running it since release with next to no problems.