This will force the non responding applications to shutdown and thus allowing the pc to shutdwon or reboot normally
1. Launch RegEdit (select Start > Run, type regedit and click OK) and browse to HKEY_USERS\.DEFAULT\Control Panel\Desktop
2. Find the string called AutoEndTasks. Right-click it, select Modify from the pop-up menu, and change the data value from 0 to 1. (If you can�t find this string, create it by selecting Edit > New > String Value and set the data value to 1.)
3. Close RegEdit and reboot.
hope that helps