Macbook late 2009 Magsafe light not turning on and baterry light flashes

So I have a really old MacBook from late 2009 (with removable battery) it ran out of power but my Magsafe wasn't working at all so o bought a new one. Problem is that when I plug it in, Magsafe light doesn't turns on (no light at all) the only sign is that when I plug it, the light on battery flashes and stays like that forever, but not charging at all and I can't turn on the Mac. Is this a problem with the battery? Is it my MacBook? What can I do to make my laptop work again?