They won't check you when you enter. When you go thru US custom the agents may pick and choose some travelers to check thier luggages to make sure there is no drugs, firearm, plants and animal. Before you arrive, you'll have to fill out a custom form. Make sure read carefully.
Then, when you come back after you check in at the airport, you have to go thru TSA security before going to the gate. You'll have to make sure you put your laptop on a separate tray. Some security agects may ask you to turn on the computer to make sure that is not a bomb. One very important thing, make sure you have no more than 100ml total of liquid or gel substance in your carry on luggages. If the items do not fit into the small bag that the airport provides, they will be confiscated.