2007 Macbook Pro not charging

I recently got a new magsafe power cord because my old one had apparently stopped working.

On the old cord, the orange light indicating charging wasn't showing up, so I assumed it was broken. Got a new cord, and things were fine until recently I noticed that occasionally the light won't turn on when I plug it in. Usually I just close my laptop, take out the battery and put it back in, and charging will resume, but I don't want to have to keep doing this. I looked at the specs for my computer's battery and I'm only at 577 cycles and the condition is 'good'. Does anyone know what could be wrong with this? I figure I just need to get a new battery, but this is pretty bizarre.