Figured it out. Thanks anyway.

I had to reformat my hard drive and reinstall programs. I have reinstall ed Pegasus Mail and old messages are backed up. Unfortunately, I am not sure which files are messages and which are addresses, etc. So I have two questions; what is the file extension name for messages and where in the Pegasus file structure should I move saved messages? Also what is the file extension name for addresses and where should they be located?

http://www.vandenbogaerde.net/pegasusmail/pf_pmfiles.html

Also the white paper found here:

http://community.pmail.com/files/folders/whitepapers/entry41852.aspx

Both of these help to some degree. Please tell me if this is accurate: I can copy saved messages (in a backup using carbonite) and paste them in the appropriate file folder in Pmail and I will be able to read them. Is that true?

Depends on the backup. I know nothing of carbonite. Does it back up the mailbox as a whole, including folder pairs?

There are varying levels of complexity depending on your original installation and your new one.  I the orginal installation was installed in the default locations of C:\Pmail\Programs and C:\Pmail\Mail and had the default user of Admin (mailbox directory of C:\Pmail\Mail\Admin) then you could do a new installation, configure it enough to get the Admin mailbox directory created, and then replace it (copy it first just in case) with the Admin mailbox directory from the backup assuming carbonite has a full backup and not a bunch of differential ones.  It is imperative that the installation paths of the new install are identical to the old or this will not work. 

If you have already created a folder structure and have downloaded messages in the new installation that need to be preserved then you must restore data files from the old mailbox backup to the new mailbox directory as per the documents.

Carbonite is a backup program that saves marked files to their server. Access is thru the internet. Since I am not sure where the "mailbox" is, I can't say for sure whether "folder pairs" are copied. I believe I have the correct files marked so that they were backed up. Files with the following extensions: pmm, pmi, pm, pns, pml and cnn were saved in a file named "mail". Would any of these be messages?

Thanks for your suggestions.  Files with the following extensions: pmm, pmi, pm, pns, pml and cnn were saved in a file named "mail". Would any of these be messages?

Yes. Files with the extension CNM are new mail messages and are single files within the mailbox.

Folder pairs are two files with the same name but differing extensions PMI (index file) and PMM (message file) also within the mailbox. Restore both.

Refer to Han's list for the full rundown. 

So I can move files with the extensions "CNM" and "PMI" and "PMM" to the file location of "PMAIL/MAIL/ADMIN"?

I jus tried moving archived message files to the Pegasus folder. There doesn't appear to be any way to read them. I am at a dead end as far as trying to read old messages. 

I have made extensive use of lists and have found the files that contain all the email addresses. I have recreated my lists. However, I don't know how to identify entries to my address book. Can you help?