LIGHT WORK RADIO WORKS, CAR CLICKS WHEN YOU TURN

Poor connections between the battery and the battery terminals can allow enough power to run lights and radio and NOT provide sufficient level of current to allow the starter to turn the car over.
A 4 year old battery is most likely the culprit, but before you change it out, attempt to clean the terminals with a battery terminal brush. Clean the battery posts and inside of the terminals to make sure that there is a good connection. BUT usually batteries of this age are suspect...alot of times, the changes in weather will emphasize the problem of a bad bat.

if the blinkers are flashing like normal speed then most likely no. Try cleaning the battery. If still clicks you prabably have a bad starter.

Could be.