Does Lenovo 3000 Y410 support dual monitors - Lenovo 3000 Y410 (59012354) PC Notebook

Yes.

1) Laptop OFF, monitor OFF.
Connect a VGA monitor to the VGA port, on the back of the laptop.

The VGA port is on the right side, as you view the back of the laptop.
This is a basic example of a VGA cable, and a VGA port, (Connector),

http://en.wikipedia.org/wiki/VGA_connector

NOTE* Color does Not matter.

You can use a CRT monitor, (Looks like a small TV), or a flat LCD screen monitor if it has a VGA cable.

Turn the monitor on. If a CRT type allow it to warm up.
Turn the laptop on.

By default the display should show on the external VGA monitor.

IF not;
Press, and hold down on the Fn key, and at the same time tap once on the F3 key.

No?
There are at least 3 display options;

1) Internal monitor of laptop ONLY

2) Internal monitor of laptop AND external VGA monitor

3) External VGA monitor ONLY

Hold the Fn key down, and tap again on the F3 key.

(The Fn key is down at the bottom LEFT corner of the Keyboard.
The F3 key is at the top of the Keyboard.
The F3 key is the Display Toggle-Over key )

Need more information post in a Comment.

Regards,
joecoolvette