Margaret, if you click on Windows File Explorer, look at c:\users\<yourid>\appdata\roaming\thunderbird\profiles. If this folder exists, then click any folder inside it and look for a file called abook.sqlite. That would be the addressbook. If File Explorer does not let you view the folders, you can click View>Show>Hidden items in File Explorer. The folders will be there if all you did was uninstall Thunderbird, but there is a final prompt on an uninstall on whether to keep data, so it's possible you may have deleted it.

If you have done a new install, there may be more than one folder in the Profiles folder, so look for the oldest and largest abook.sqlite. Let me know if you need more assistance.