Get Disk Serial Number

 function GetDiskSerialNumber(Disk: char): string;
var
  VolumeSerialNumber,
  MaximumComponentLength,
  FileSystemFlags: DWORD;
  SerialNumber: string;
begin
  GetVolumeInformation(PChar(Disk + ':\'),
                       nil,
                       ۰,
                       @VolumeSerialNumber,
                       MaximumComponentLength,
                       FileSystemFlags,
                       nil,
                       ۰);
  SerialNumber := 
   Format('%.4X-%.4X', [HiWord(VolumeSerialNumber), LoWord(VolumeSerialNumber)]);
  Result := SerialNumber;
end;