Check is Programm Installed

uses ActiveX

//

function ProgIDInstalled(const PID: string): Boolean;
var
  WPID: WideString;  // PID as wide string
  Dummy: TGUID;      // unused out value from CLSIDFromProgID function
begin
  WPID := PID;
  Result := ActiveX.Succeeded(
    ActiveX.CLSIDFromProgID(PWideChar(WPID), Dummy)
  );
end;

function IsIEInstalled: Boolean;
begin
  Result := ProgIDInstalled('InternetExplorer.Application');
end;

Beispiel :

procedure TForm1.Button1Click(Sender: TObject);
begin
  if IsIEInstalled = true then
  label1.Caption := 'yes'
  else
  label1.Caption := 'no';
end;