flash actionscript: Can anyone help me on this important problem?

Two mounths ago I started to work on a project using "Macromedia Flasm MX 2004
Professional" and when I did about %60 of that project - which took a mounth -
and after that I destroyed my windows - which had got too old - and installed a
new fresh one.
After that, I installed the same version of the Flash which I used to use; but
when I want to open those files, it says : "Unexpected Format"!!

It can open the files I had worked in Flasm MX 2003 and older; but not any of
those in Flash MX2004 Pro....
and also the SWF extension of those files still work; but not FLA source
files...

PLEASE somebody help me; a moounth of my work on this project is ruined...