The beach ball keeps spinning and does not log-out

The Control + Command + Disk eject keys will force a restart on a Intel based Mac that is logged in and Command + shift + q will log out users. Some operations will halt restarts, shutdowns and log outs. You need to find the application causing the beach ball and fix it. You may find the offending program by checking the console for problems the Console is in (Applications-Utilities-Console).