Code:

uses

Registry;

procedure AddFileMenue(FilePrefix, Menue, Command: string);

var

reg: TRegistry;

typ: string;

begin

reg := TRegistry.Create;

with reg do

begin

   RootKey := HKEY_CLASSES_ROOT;

   OpenKey('.' + FilePrefix, True);

   typ := ReadString('');

   if typ = '' then

   begin

     typ := Fileprefix + 'file';

     WriteString('', typ);

   end;

   CloseKey;

   OpenKey(typ + '\shell\' + Menue + '\command', True);

   WriteString('', command + ' "%1"');

   CloseKey;

   Free;

end;

end;

procedure DeleteFileMenue(Fileprefix, Menue: string);

var

reg: TRegistry;

typ: string;

begin

reg := TRegistry.Create;

with reg do

begin

   RootKey := HKEY_CLASSES_ROOT;

   OpenKey('.' + Fileprefix, True);

   typ := ReadString('');

   CloseKey;

   OpenKey(typ + '\shell', True);

   DeleteKey(Menue);

   CloseKey;

   Free;

end;

end;

{ Example}

procedure TForm1.Button1Click(Sender: TObject);

begin

AddFileMenue('rtf', 'Edit with Notepad', 'C:\Windows\system\notepad.exe');

{

   If you now click with the right mousebutton on a *.rtf-file then

   you can see a Menuepoint: "Edit with Notepad".

   When Click on that point Notepad opens the file.

}

end;

procedure TForm1.Button2Click(Sender: TObject);

begin

{

  Undo your changes in the Registry:

}

DeleteFileMenue('rtf', 'Edit with Notepad');

end;