It sounds like your drawing template setting locations are no longer pointing to the previous templates. Check this by going to Tools/options/system options/file locations and templates.
What you need to do prior to upgrading is to use the Copy Wizard to save all your settings, however some people don't recommend to use it from one version to the other, but I never had any issues that I'm aware of. Another thing that I do is to go through the every option in the Tools/Option dialog box and take a snap shot of every possibile option including color and line fonts etc... and paste them in a Microsoft Publisher file, page by page, now I have a manual stop check. The other thing I would recommend is to save your Drafting Standards as well..