Look in the manuals that came with the computer or look in your device manager- display adapters.
I just got a Gateway Multi-Media-Center PC and I don't know how to find what type of graphic card is in it and Gateway refuses to anwser my question. I want to play Roller Coaster Tycoon 3 and it recomments an ATI Radeon 64MB SDR, or a GeForce2 Pro 64 MB. When I told the Gateway tech a problem I was having she very rudely told me I needed a different graphic card. I am new to this, where do I find what this machine has in it.