Acer Aspire 5100 Power problems.

Okay, so my 5100, pretty old, four five years maybe, just decides to randomly stop charging when the laptop was, running, and in use. Then it pretty much ran out a juice within the next five minutes of me trying to fix it. So, later on I try and do the power reset thing (unplug battery, hold power button in, etc.) and it didn't work. Without the battery in, it doesn't boot up at all. Once its in, it'll shutoff a about a second after I turn it on. I makes like this noise when it shuts off but it sounds like the same noise I've heard whenever I shut it off, and its been like that since I got it. It seems the battery receives enough power to turn on, but not boot up Windows XP. Over time, I've upgraded the RAM, the wireless card went bad so I had to fix it. That's all that has ever happened. The wireless card broke about a year or two ago, so its not that. I've also tried plugging it in to different outlets, fiddling with the power cord (not opening it or anything, just like shifting it around and stuff), and I fiddled with the part that goes from outlet to powercord.

Thanks to anyone that can help.