Just picked one up. 13 year old key fob. Seems the only way into the car is by putting key into lock. Seems odd that the fob does not permit keyless entry???
If it's the old, the switches on the circuit board may have worn out. They are simple to replace if you know what you're doing. If not any decent electronics repair shop should be able to do it.
If it's the new one, it sounds like it's broken, but was it ever linked to the car?