trouble getting car started
 

i have a 1995 c280 i am having trouble getting my car started sometimes. i have had it into shop and they said the motor controlling the antenna was draining the battery so they disconnected it. that was not it i am still having the problem but it does not happen every time i start it. however sometimes all the settings have to be reset (clock ,radio, etc) then some days it starts fine . what could this be? also my windshield wiper is not working properly could this have anything to do with this problem? my battery is only 1 year old.