You could always open up your computer and see what it says on your video card(it should the name of it somewhere). You can also right-click on "My Computer" click properties, go to the hardware tab, then click device manager, click "Display Adapters" and it should tell you what you have.
If you want to play Guild Wars then make sure you at least have a 9800 Pro or an equivalent of it if you want to play on high settings.