Robot won't run straight

I am a PLTW Launch teacher, and I have tethered and connected the brain to the controller, and it all looks like it should be connected. When using the remote, the robot goes in circles and will not go straight or in reverse. Help?

You may have a badly calibrated controller, try recalibrating it. You also may have a problem with one motor on one side. On the slower side, check the connection to the axle, and try replacing the motor with a different motor.

Aloha bhlogan,
Are you using the pre-loaded program on the brain or did you write your own? If it is the pre-loaded code make sure that the wires to the motors are plugged into the correct slot. Then check that the axel is pushed all the way in as Paul mentioned. Let me know if that works.