Unable to run the regedit.exe file

Hello,
sir i what to run the registry of my windows xp pro sp2 OS. ONCE I HAVE changed the SETTING OF regedit.exe.
as i want to run it now it is now unable to run at start->run command and the OS is displaying the message as the registry is disabled by the administrator. after that my system is restarting. please help the alternate way to open the registry inorder to edit.


Thanking you sir,
kumar