Well, it can be a bit tricky.
Since you don\'t know how to check that, I also assume that you have never updated your drivers and then therefore you need to do that.
You have first of all to find out which is your graphics card. If you are under Windows (I assume so) you should click with the right button of the mouse on the desktop, then properties, then settings and then you should read, under the image with the screens the name of the graphics card.
When you know which is it, you have to go to the graphic card vendor homepage. Usually, in the support or download page they provide the possibility to download the new drivers.
Check for the name of your card and download and install the latest driver.
If something is not clear, please just ask.