The problems
A bad decision by Microsoft in the design of TweakUI can render the control panel inaccessible. The ‘Show Control Panel on Start Menu Settings’ option, if unchecked, removes the Control Panel not only from the Start Menu, but also from My Computer. Even worse, if users do access the Control Panel (through a separate shortcut, for example), attempting to change any settings gives the following useless error message:
The operation has been cancelled due to restrictions in effect for this computer. Please contact your system administrator.
The fix
Some people have resorted to System Restore to fix this problem, but there is an easier method. Click on Run… in the Start Menu and enter ‘regedit’ to edit the registry. (Standard Disclaimer: if you mess up the registry it can make your computer unusable. If you follow these instructions incorrectly, I accept no responsibility for any damage caused.) In the Registry Editor, use the Find function in the edit menu to search for ‘NoControlPanel’ — make sure the boxes for Keys and Values are checked. Depending on which version of Windows you’re using (I believe the problem only effects Windows ME and Windows 2000), one or both of the following may come up:
- The value ‘NoControlPanel’ under ‘name’ in the right-hand window pane (this will be part of the Key HKEY_CURRENT_USER/Software/Microsoft/Windows/CurrentVersion/Policies/Explorer). Right-click on ‘NoControlPanel’ and delete it.
- The key ‘NoControlPanel’ in the left-hand window pane — it will look like a folder (this will by the Key HKEY_LOCAL_MACHINE/SOFTWARE/Microsoft/Windows/CurrentVersion/explorer/StartMenu/StartMenu/CascadeControlPanel/Policy/NoControlPanel). Right-click on ‘NoControlPanel’ and delete it.
After this, close the Registry Editor and the problem should be solved (you may need to reboot the computer first).