when you say "back to htm file" that leads me to suspect you are not properly
creating and maintaining a web publication.
Did you create a .pub file?
After you create a new web publication you save it as the .pub file.
That pub file is the site entity. It is what you modify, you do not modify
htm files.
From the pub file you use File, Publish as ... to generate the html and
image files that comprise the web site and are uploaded to a server.
The pub file and the web site files are separate entities. Refer to what I
wrote on http://www.publishermvps.com/WebDesign/tabid/29/Default.aspx - left
side column.