Could be spyware slowing you down. You playing on. Or bad internet latency if on line. We need your computer spec.and if your playing on line or off, along with internet connection details if so.
AHA! So its a Dell! That explains everything. Just kidding. Your anti aliasing might be on. Can you please tell me how much ram you have? How big your graphics card is? And how much hard drive space you have. Thanks.