Won't start after battery replacement

Long winded description.

My track pad was getting hard to push, and through googling I figured out it was most likely due to the battery. I had also read that I should be able to run the macbook pro without the battery. I ordered a new battery and since the wait wasn't long, I decided to go ahead and take the old battery out. It wouldn't turn on after that, so I decided to just let it sit a day and wait for the new battery. Installed the new battery and nothing. I tried an SMC (keyboard) and that didn't work. I then unplugged the battery and power cable held the power button, replaced both and it came on, but the battery indicator was showing an "X". In the system profiler it said no battery was installed. I restarted it, and the same thing happened. Next Instead of restarting I just shut down, and it wouldn't restart again after that. This whole time I notice the light on the mag safe plug is very dim green. While plugged in the second closest to the front battery indicator light stays on, and if plugged in for a while remains on when removed. I ended up getting the computer to start one more time last night with the same problem, so I was going to try a restart and hardware test, but when I tried that it just shut down at the apple logo. I left the computer plugged in last night and got to the apple logo again this morning after unplugging the power and battery and holding the power button for 10 seconds, but only got to the apple logo again trying to perform the hardware test.