Pontiac grand prix 2004 battery starter alternator

Sounds like your battery is being drained by something. Double check that all electrical items are off. Things like glove box lights, audio systems, power accessories, courtesy lights, etc. often get overlooked and, if left on, will drain the battery. If you don't find anything, you will need to confirm you are draining the system by having a Amp Meter connected in series between the positive battery terminal and (after disconnecting it from the battery) the positive battery cable. You should see a reading greater than zero on the meter. Then begin to pull out fuses from you fuse block until the meter goes to zero. This will tell you what circuit is causing the problem.and you can then go about trouble shooting components on that circuit. Be patient or take it to someone familiar with electrical systems.