As Microsoft also says, Dual Monitors are better than single monitors sometimes. You can use 2 monitors in Windows XP, Windows Vista as well as Windows 7. And in Windows 7, this procedure to set ...

Locks cursor to specified window and/or converts windows to borderless fullscreen, and prevents the cursor from spilling into another monitor ...

Acer launched new portable monitors, including the PD163QT (15.6-inch touch) and PD243Y E (23.8-inch 100Hz). Both can fold up to 315° for dual-screen use, ideal for multitasking and collaboration.