You don't have to recover old local backups. By local backups, I guess you mean the automatic backups that Notezilla takes on the local hard drive. You can sign in to Notezilla.Net, and you should see your latest notes if you have been automatically syncing notes. When you sign in, you will see the notes that synced just before the reinstallation. Also, sticky notes in Notezilla sync every minute.
Here's a short video on Notezilla 's sync feature for more clarity: