Insufficient Privileges

• If you do not have administrator privileges on the computer you are working with it is possible that the settings do not allow you to use the Regedit program. This is set by the person that has administrator privileges using the local group policy editor. When you try to run Regedit and it closes with a message stating that you are not allowed access you will have to contact the person who sets the privileges on the computer.
  
  

Errors with the File

• Attempting to run Regedit with the result that it closes or gives error messages can be an indication that the actual file is corrupted or missing. Navigate to the folder on your hard drive where your copy of Windows is installed and look for the "Regedit.ext" file. If the file is missing, you will need to use the "Repair" option after inserting your original Windows install disk. If the file is present, try to copy it to another location and see if you get any error messages. If you get error messages while trying to copy the file, it is possible that it is stored on a damaged section of your hard drive.
  
  

Memory Errors

• Although rare, it is possible that another program you have run on your computer has crashed and is negatively influencing everything else. In order to determine if this is the case, save all your work and then reboot your computer to clear the memory. Try to run Regedit again and see if it still causes problems. If not, reboot and start up in "Safe Mode," then try again. As a last resort you can perform a system restore to see if you can roll back any changes that could possibly have caused this error.
  
  

Virus or Malware Infection

• A virus or malware infection is one of the most common reasons why Regedit closes when you try to run it. Because these programs make alterations to your Windows registry, they will try and prevent you from undoing their damage and removing them. Run "MSconfig" from your Start button menu and if it also closes down, you can be sure it is the work of a virus or malware program. Run a thorough scan using updated anti-virus software to solve this problem.