How do I recover and then delete my old account?

I was trying ot login my personal google account on my school computer. There were some issues with my original account, you see, I changed my google password account, and because of that, I can't access my original account. I can only access my new account that I accidentally set up and now I don't know what was the original password, is there anyway that you can possibly tell me what my original account password is, and of not, can you delete my original account so that I have the new account as my main and not have to worry having some complications.