__fastcall TForm1::TForm1(TComponent* Owner)
    : TForm(Owner)
{
}
char* (__stdcall *GetIDESerialNumber)(BYTE);

HINSTANCE DllInst = NULL;



void __fastcall TForm1::Button1Click(TObject *Sender)
{
  if (DllInst == NULL) DllInst = LoadLibrary("HardwareIDExtractorC.DLL");
  if (DllInst)
  {
    GetIDESerialNumber = (char* (__stdcall*)(BYTE))GetProcAddress(DllInst, "GetIDESerialNumber");

    //Now call the imported function
    Edit1->Text = GetIDESerialNumber(0);   // 0 = first IDE hard drive in your system 
  }
}


void __fastcall TForm1::FormClose(TObject *Sender, TCloseAction &Action)
{
  if ( DllInst ) FreeLibrary (DllInst);
}