Hey, when I bought my C240 the previous owner had the key fob but it hadn't worked for them since they got the car so I don't know when it started but the key fob wont unlock or start the car. I've done the link thing with the ignition but still nothing. It has a charged battery and the infrared light works, I still have the spare so I can still drive around normally but using the fob would be a lot easier. Hopefully someone here knows a solution to this problem

IIRC, the door handle has an infrared sensor. Get right up on it and see if you can use the fob. If that works, then the problem is the radio part of the fob. Go around to the back of the car (you'll have to Google the location of the antenna pickup for your car.) Get right up on that and try the fob. If it works, the radio amp is blown and needs replaced. If it doesn't work, I'd suspect the fob itself.