Taskbar window name is 'Shell_TrayWnd'. Use FindWindow function to find Taskbar handle, and EnableWindow function to disable/enable taskbar. For example:
var TaskbarHandle: THandle; ... procedure TForm1.FormCreate(Sender: TObject); begin TaskbarHandle:=FindWindow('Shell_TrayWnd', nil); end; procedure TForm1.Button1Click(Sender: TObject); begin EnableWindow(TaskbarHandle, False); end; procedure TForm1.Button2Click(Sender: TObject); begin EnableWindow(TaskbarHandle, True); end;