On a roll..another C240 issue
 

My windows and sunroof will no longer open using "one touch" option on the key. What gives? It gets awfully hot during the summer here in the south, my car is black, so I would like to let it breathe before getting into it! Any suggestions greatly appreciated.

You've just changed your battery, of course. (Or it went dead)

Read how to reset these things following battery change in your owners manual.