There are two ways to delete a key from the Registry from the Command line. At the Windows Command line:
RegEdit /l location of System.dat /R location of User.dat /D Registry key to delete 
   You cannot be in Windows at the time you use this switch. 
Or you can create a reg file as such: 
   REGEDIT4 
[-HKEY_LOCAL_MACHINE\the key you want to delete] 
   Note the negative sign just behind the[
   Then at the Command line type: 
   1. RegEdit C:\Windows\(name of the regfile). 
