If you're using POP or IMAP in Outlook, it's found that occasionally profiles and settings go a little wonky or software hooking into Outlook won't work any more (we've found that early Blackberry Desktop software can crash when you sychronise and you need to delete and recreate your profile to fix it)
You may want to move your mail settings to a new PC, or perhaps you need to backup of your mail settings for another reason. Either way, here are various methods with which to back up your Outlook Profile settings.