ADamnHD :
Basically i just got a new monitor i wanted to use as a 2nd monitor but when i connected it to my PC via VGA cable it isn't recognised by my PC at all, just my main one, it worked on a friends PC but not mine, help
Right-click the desktop, and select Properties or Personalize. Select Display Settings from the list of preferences.
You should see icons with numbers representing your attached monitors. If one is disabled, it will be grayed out. If the second monitor can't be found, press the "Detect" icon and the monitor should come up.
Select the second monitor and choose to extend your desktop
Your options may be dependent on the graphics card that you have installed. You may need to make these changes from within your nVidia or ATI control panels. If you have these installed, they can be found in your Start menu.