Description

Add WinSvc to uses then use this code.

Delphi code

procedure TForm1.Button1Click(Sender: TObject);
var
  SCManHandle, SvcHandle: THandle;
begin
  SCManHandle := OpenSCManager('Your_Machine_Name', nil, SC_MANAGER_CONNECT);

  if (SCManHandle > 0) then
    SvcHandle := OpenService(SCManHandle, 'Service_Name', SERVICE_QUERY_STATUS);

  if SvcHandle > 0 then //is service installed then .....
  //...

   CloseServiceHandle(SvcHandle);
end;