To check to see if it is the batter, take to screwdrivers (with insulated handles) and touch each screwdriver to each side of the solenoid (one to each side) and then touch the two screwdrivers together (it will spark and smoke etc, not to worry!) this will send a full power surge to your starter. If the car starts, you have a weak battery, if it still just clicks, you have another problem (not the battery) - this is called jumping off the solenoid