internet connectivity, dropped connections........

I certainly hope someone can help me. I have a new Macbook Air and I am continually getting booted off the internet. My computer drops the connections, then I get a message "finding network". How do I keep the connections from coming and going like this? I already checked with my ISP and there is no ISP issue. Since I am a new Apple user, I do not know how to change the settings. Please someone help me, as I am getting tired of dropped connections. Thanks..