function GetHardDiskSerial(const DriveLetter: Char): string;
var
NotUsed: DWORD;
VolumeFlags: DWORD;
VolumeInfo: array[0..MAX_PATH] of Char;
VolumeSerialNumber: DWORD;
begin
GetVolumeInformation(PChar(DriveLetter + ':\'),
nil, SizeOf(VolumeInfo), @VolumeSerialNumber, NotUsed,
VolumeFlags, nil, 0);
Result := Format('Label = %s VolSer = %8.8X',
[VolumeInfo, VolumeSerialNumber])
end;
procedure TForm1.Button1Click(Sender: TObject);
begin
ShowMessage(GetHardDiskSerial('c'));
end;