my MB-C320 2005 MODEL keeps flashing on the screen that my lights are on when i had already put them off and my battery keeps draining

reset everything. Perhaps your battery is going soft on connections. Hose off all corrosion and wire brush the contacts clean, don't forget the ground wire and connection to the frame and engine. All should be solid connections. The computer is suffering from 'brown out'. Reset the best you can, pullin the red terminal off the battery to clean it should put you right. Will have to adjust the clock.

headlight relay could be stuck in the 'on' position.