Why does my Xbox guide button flick on and of?

Hi, iFixit. I have an Xbox 360 wireless controller. I've been having this controller for 2 years. Well my problem is when I hold the Xbox guide button to turn it on it turns on but doesn't work. The green light just flicks on and of and just does that the whole time. I always put new fresh batteries but it does the same thing. I was wondering if u could answer my question please. Thank You