Hi,
I am using a geforce 220 graphics card, I have one monitor plugged into the gpu by a VGA cable and the second monitor (which is not working) by a VGA to dvi adapter. Why is my second monitor not working?!
Assuming Windows, go to Control Panel/Nvidia Control Panel and click on it. On the next window select Display and 'Set up multiple displays' put a tick in both display boxes and then adjust to suit.