I've been researching this in Google and Microsoft's Knowledge Base, and can find little reference to it, except one article in Microsoft, here at this link
Unless anyone else knows how to help, have a look at that.
When did this start to happen? Was if at any particular point? ie did you install something, or re-instal XP, or something else?
Have you tried to access any of the Control Panel Applets whilst in Safe Mode, or access Display Properties thru right clicking the desktop in Safe Mode?
When I open the control panel it opens normally but when I click on one of the items in control panel ("Display" or "User Accounts" etc.) nothing happens-they won't open. Also if I try to get to the display properties by clicking on the blank section of the desktop and then choose properties, it will not open. Other than this the system seems to be operating normally. This is Windows XP home.