|If it's actually displaying the "no signal" message, it means the LCD monitor itself is okay at least. |
Try a new signal-cable (VGA cable).
If still no luck, check the primary/secondary monitor settings on your laptop with the (LCD monitor connected to it of course). The settings are in Control Panel > Display
The only other possible cause I can think of is that the external monitor port on your laptop is faulty, in which case your Display Settings on your laptop would not show a secondary monitor since it would not be detected.