Need Help Putty Arduino Mega 2560 and Arduino shield 2.1


I'm a beginner about using Arduino and I have to do an internship using Arduino and I'm wondering if someone can help me to solve one of my problems,here the thing I'm using putty to configure the wifi shield since the wizard don't actually work,so I use the AT commands but now I don't why when i'm launching putty I can't type any commands and there is like encrypted code on it and if I press and hold reset button I can write command but when I release it I can't do anything and I see the encrypted code.... Any helps would be appreciate (my project is to control an arduino minicar with a webcam on it using the wifi connecting on a eee pad transformer)

Regards Nhan57