How do I control NES games on my PC?

I downloaded NEStopia, and the only way I can control the NES games are by using my keyboard. I wanted to have a hand-held controller so I bought a "Logitech Dual Action" USB controller today and I installed it, but it still has no effect on the games, it doesn't work. I don't know if it's not compatabile or what, but I hope somebody can help me out. How do I get a USB controller to work on NES games?

Nevermind! I figured it out..I configured it..wow, i can't believe i'm playing kid icarus!!!

I'm glad you were able to help yourself with your problem
emulators are not that hard to figure out... if you just explore and mess around with the program (that goes with any other program too)