The following example silently installs a print driver. You will need to copy the print driver files to the Windows\System directory and add the following entries to the Win.Ini file.

Notes:
In the follwong example:
   DriverName = Name of the driver;
   DRVFILE - Filename of the driver minus the extension
             (unless it is not ".drv").
Example:
procedure TForm .Button Click(Sender: TObject);
var
  s : array[0..64] of char;
begin
  WriteProfileString('PrinterPorts',
                     'DriverName',
                     'DRVFILE,FILE:, 5,45');
  WriteProfileString('Devices',
                     'DriverName',
                     'DRVFILE,FILE:');
  StrCopy(S, 'PrinterPorts');
  SendMessage(HWND_BROADCAST, WM_WININICHANGE, 0, LongInt(@S));
  StrCopy(S, 'Devices');
  SendMessage(HWND_BROADCAST, WM_WININICHANGE, 0, LongInt(@S));
end;