hello ,
I bought my Deville 2001 a week ago and last night the car would not start it had no power. Had to jump start the car. Once it turned over it was fine until I turned it off. Can any one give me any suggestions on what needs to be done. I think it might be the battery but im not a car wiz.

 

sounds to me your batery is shot. because you say it has no power which would make me think it has a dead cell,which causes the battery not to hold a charge. Also when you start your car you use the battery so after the car starts the alternator takes over and does all the work including charging the battery which sounds too me that your battery wont get charged up and hold a charge. so i would get another battery.
good luck.

 

thanks