i think its a generator issue

[mitchbar]

lately my 64 mustang has been acting up. when i go to start it, it will just click once and the engine will not crank or anything. then i jump it and it starts then runs for a few days and then it does it again. i know it is not a battery problem since i just bought a new battery last week. what does anybody think it is. is it the generator and if so how do i get it checked out to be sure or are there any tests to see what the problem could be?