And http://www.howtogeek.com/forum/topic/outlook-2007-account-settings makes me think it's difficult or impossible now. It seems you just have to reenter the accounts.
Reentering accounts shouldn't be a problem since ISP's use to have instructions on their site and you surely saved username and password with all your other usernames and passwords in your password manager, didn't you? Just in case you didn't: http://keepass.info/download.html is the one I use, but there are others (free and paid). If you work on multiple devices, one that stores them in the cloud might be useful.