The Battery is Not Registered By My OS?.

My macbook died a while ago (due to what I believe to be a hard drive issue) and sadly unknown to me leaving the batter dormant would leave issues I have swapped the dormant batter out. The new battery is currently in place and the charger light is still shining solid green as though it were charged which I know is not the case the battery is not registering with the computer is there any way to remedy the situation?. I have already reset the smc and attempted what measures I could. The boot self test passes and the loading spiral continues to spin on several occasions I have gotten the machine to the loading of the log in screen what I am curious to know is the hard drive loose or partially disconnected in some way?. I know I am asking about a hard drive issue but if anything software is involved with this I am unable to remedy it as I am unable to log into my account to do so. I have not done any serious repair work on a mac in a long time and I could truly use the help.