unit Unit1;

interface

uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls;

type
TForm1 = class(TForm)
Button1: TButton;
Memo1: TMemo;
ListBox1: TListBox;
Button2: TButton;
procedure Button2Click(Sender: TObject);
procedure Button1Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;

var
Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
var
Buffer: array[0..500] of char;
hChar: pChar;
begin
GetLogicalDriveStrings(Sizeof(Buffer), Buffer);
hChar:= Buffer;
while hChar[0] <> #0 do
begin
ListBox1.Items.Add(hChar);
hChar := StrEnd(hChar) + 1;
end;
end;

procedure TForm1.Button2Click(Sender: TObject);
var
ld : DWORD;
i : integer;
begin
ld := GetLogicalDrives;
for i := 0 to 25 do begin
if (ld and (1 shl i)) <> 0 then
Memo1.Lines.Add(Char(Ord('A') + i) + ':\');
end;
end;

end.