Why don't you just go and set up the account in webmail and see what's there? If you're already using outlook.com then you probably don't need to move anything. If you have been using POP in Thunderbird and therefore it has the sole copy of some of your messages, come back and say so and someone will help you with getting them back onto the outlook.com server. Thunderbird is just an email client on your computer. It isn't an account and if you just stop using Thunderbird it will stop collecting messages. There is no need to forward anything - unless there is another non-outlook account you haven't told us about. As for contacts, export each of your address books to a CSV file then find out how to import these files into the outlook webmail tool.