.fla vs .swf edits

I noticed that I am able to import a Flash .swf file into a new document and even see the many component parts listed. I did not know this was possible.

Does this mean I can easily re-edit the movie and make it work somewhat like the original?

I say somewhat because the swf file I imported was missing the sound which I think was maybe not embedded in the original movie.

We lost the orginal .fla file that the old webmaster have but we cannot reach him. We really need to edit only the automatic links in the file.

I am trying to find a work around this as it is the intro page to the whole site which takes visitors to the main page but now I need to give them options to go to either an English or Spanish page.

Thanks
Dave