Recover deleted email account

I had an email account set up as a POP account in Thunderbird. I had to switch it over to IMAP so it would sync with my online email account. I was told to delete the POP account and set up the account from scratch as IMAP, and of course when I did so, all of the emails and folders I had in Thunderbird disappeared. I found the link for "Recovering deleted mail accounts", and I seem to have found the profile, which contains the files of all my old email folders, but I cannot figure out how to get them to import into Thunderbird to recover my deleted mail and folders. HELP!!!