{uses
ActiveX,ShlObj}

unit Unit1;
interface
uses
 Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs,ShlObj, ActiveX;
function GetSystemPath(Folder: Integer): string;

implementation
function GetSystemPath(Folder: Integer): string;
var
PIDL: PItemIDList;
  Path: LPSTR;
AMalloc: IMalloc;
begin
Path := StrAlloc(MAX_PATH);
  SHGetSpecialFolderLocation(Application.Handle, Folder, PIDL);
  if SHGetPathFromIDList(PIDL, Path) then
    Result := Path;
  SHGetMalloc(AMalloc);
  AMalloc.Free(PIDL);
  StrDispose(Path);
end;
end.

{Kullanım}

var
yol:string;
begin
yol:=GetSystemPath(CSIDL_DESKTOP);
showmessage(yol);