One Note 2013 versus One Note for Windows 10

I truly love OneNote 2013 but I decided to try OneNote for Windows 10.  I installed it on 3 computers. I thought they were syncing to each until I found that one had no password entered and so syncing stopped and I'm trying to solve this problem.   I find that I have different sign-in information on one or more of the computers, which is hindering the logins.  So right now I would really like to get back to just OneNote for 2013.  How and where do I begin to get rid of the new version and keep my original without losing years of data?  Thanks to all who try to help.