You mean your Display Adapter which is actually your Video card...
See in Right click My computer>Hardware>Device Manager or Start >Run type dxdiag and look at the Display tab , to see what Video card you have. (manufacturer, type)
Then go to the manufacturer's website and download the driver of your video card model.
Or, go right click My computer>Hardware>Device Manager , locate your video card, usually under Display adapter, double click it and go to the driver tab and click update. Let it search the web for an update.