I dropped my model No. A1241 phone and the touch screen doesn't work but it has no cracks. how can I fix it?

If it keeps refusing to recognize the touchthere may be an issue with your digitizer. You can get the part at iphone 4S Repair and there is a guide that shows you how to put in the part at iPhone 4S Repair Guide.

Not having a crack on the screen doesnt mean your touchscreen will work. you said you drop your phone, it has a great possibility that it cause an internal damage to some of the microchip inside your phone that controls the sensors of your touchscreen.need to reheat the microchip inside it. open your phone and try to check for the microchip near the flex from the board of your phone going to your screen. then reheat it, but dont move it.