In theory you could replace the index.html framset (or default.html if that
is what your host supports but I'm going to use index.html in the rest of
this message) with whatever is in the main content frame of your current
version. I'd do it by making a copy of the current web to test with before
doing anything else.
Then I'd open the page that makes occupies the main content frame in the
current framed site and rename it index.html. Close the file then reopen it.
Next I'd open the shared borders dialog box (Format, Shared Borders) and
select the radio button for "All pages" and check the boxes for the ones I
want to include. Finally, I'd open the shared border files (make sure that
you have "show hidden files and folders check under Tools, Web Setting,
Advanced tab) and put the content in those pages I wanted to use. Then
recalculate hyperlinks and try the website locally or publsih to a subweb if
you have bots that require server extensions to work. (Note if you do those
pages will probably require some individual edting.)
I don't use frames so I can't guarantee the above would work but that is how
I'd try it before manually changing each page. That's why I started my
instructions with first make a copy of the current website and test on it.
Note any links you currently have will need to have the target attribute
changed from the frame they should load by removing the 'target="framename"
' from the <a href tag.