Well, the most common reason you are getting low frame rate in most wanted is the you need a new gfx card. Your current card must not have enough power to run nfs most wanted. You should get at least ATi HD6670 1 GB GDDR5 to run most wanted smoothly at 60FPS.
Are you talking about nfs most wanted? or are you talking about the most wanted game out there is running slow on your PC? There could be all kinds of reasons for a game to run slow.
You should post all of your specs and add a little more info to your question. Because it looks like your are trolling. That is not a good idea, it is against the rules. I hope you reply so if you really do need we can help you.