How to lock down a computer

For Windows XP.

• Create limited user account.
  
• From admin open gpedit.msc
  
• Go to Administrative Templates > System > Run only allowed Windows Applications
  
• Define applications as winword.exe, firefox.exe etc.
  
• Don't forget whatever you do to include gpedit.msc and mmc.exe otherwise you won't be able to get back in! 
  
• Get rid of run... command.