< サンプル１ >
{$WARN SYMBOL_PLATFORM OFF}

procedure DeleteFolders(FolderName:string);
var
        SearchRec: TSearchRec;
        fname: string;
        rc, ww: Integer;
begin
    //パス名が区切り記号で終わる様にする
    FolderName := IncludeTrailingPathDelimiter(FolderName);

    rc := FindFirst( FolderName+'*.*',faAnyFile,SearchRec );
    while rc=0 do begin
        if (SearchRec.Attr and faDirectory)>0 then begin
            if (SearchRec.Name<>'.') and (SearchRec.Name<>'..') then
                DeleteFolders( FolderName+SearchRec.Name );
        end
        else begin
            fname := FolderName+SearchRec.Name;
            FileSetAttr( fname,faArchive );     {File属性変更}
            DeleteFile( fname );
        end;
        rc := FindNext( SearchRec );
    end;
    FindClose( SearchRec );

    RemoveDir( FolderName );                    {ﾌｫﾙﾀﾞｰの削除}
end;


< サンプル２ >
usesに ShellAPI と StdCtrls を追加する

procedure DeleteFolders(FolderName: string);
var
        foStruct: TSHFileOpStruct;
begin
    //末尾の区切り記号なしでパス名を返す
    FolderName := ExcludeTrailingPathDelimiter(FolderName);

    with foStruct do begin
        wnd    := Form1.Handle;
        wFunc  := FO_DELETE;
        pFrom  := PChar(FolderName+#0);
        pTo    := Nil;
        fFlags := fof_NOCONFIRMATION or FOF_NOCONFIRMMKDIR;
        fAnyOperationsAborted := False;
        hNameMappings     := Nil;
        lpszProgressTitle := Nil;
    end;
    SHFileOperation(foStruct);
end;