take a look at these pictures

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

DVI
http://www.interfacebus.com/Design_Connector_Digital_Visual_Interface_DVI_Bus.html

Old LCD monitor may require user to press a botton to switch from different input sources. Please check your manual.

First make sure the LCD monitor is OK. You can hook up another PC/laptop to test it out.

If LCD monitor, connection are OK, then borrow a video card to test out your PC. Maybe the integrated video card in your PC is broken.