If you have downloaded emails from the Freeserve mailservers in Outlook, they will still be there - they won't disappear.
All you have to do is continue using Outlook, but with a new mail account.
You can retain all your old emails if you wish, and do it in a variety of ways. Take a look at this, for example. The advantage of archiving emails is that it reduces the size of your Outlook data file. Outlook doesn't have to load all those emails each time you open it.