If you purchased the current version I think the 2017 version is a free upgrade, otherwise there is a 50% discount to upgrade, but your version should still be good as is. The last stable version of 2015 was build 1372, you can download from here. https://infinitekind.com/stabledl/
Did you load the windows 64 bit version? Do you have anything listed on the sidebar? Have you opened MD to full screen? Also when in the register, have you clicked the "all" tab at the top left of the register page? Are you using the same "data set" show at the extreme top left as you have before? Have you tried clicking Tools, Accounts, to see if your accounts are listed and have dollar amounts listed?
Also you may need to take a look at the Help, Console Window, to see if there are any glaring error messages. You might copy and paste the first dozen lines into this discussion for others to observe.