The HTML Help Registry Key

You can determine if HTML Help is installed on a computer by checking for the HTML Help registry key.

  1. Click Start, and then click Run.
  2. Type regedit in the Open box, and then click OK. This will open the Microsoft Registry Editor.
  3. Click Find on the Edit menu, and then search for the following CLSID:


    This is the CLSID of the HTML Help ActiveX Control (Hhctrl.ocx) in Windows XP SP1 and later. It is registered by the system during setup. If Hhctrl.ocx is installed on your system, the CLSID will be found under HKEY_CLASSES_ROOT/CLSID. If it is not found, Hhctrl.ocx is not installed.

Important  Use extreme caution when viewing your registry with the Registry Editor. Changing anything in the registry can adversely affect how your system functions.