Battery wouldn't charge. I replaced the cable and the battery with no luck. I needed to fix my iBook; I can't afford a new iMac. Found that the problem was in the DC-In Board was fried, surfed in to ifixit from Google and found a replacement for a reasonable price.
Pulled the old one out, put the new one in, works great!
If you have this problem, just make sure you get a new power chord as well. It probably caused the problem in the first place.