your fla is corrupt.
first check its file size. if its 0, all your work is lost.
if it's greater than 0 you may be able to recover some or all of your work.
change the name of your fla extension to rar and open in winrar and see if it can 'repair' the rar file. then rename to a fla and try opening in flash pro.
if that fails you can unrar the renamed fla and there may be some assets you can import into a new fla.
as an alternative to working with the fla, if you have a working swf, you can decompile it to recreate the fla. imo, sothinks decompiler is the best.
lastly, never do that again. periodically save your fla with increasing version numbers.
for example, for a project named mapKeys, i'll use mapKeys_01.fla, mapKeys_02.fla etc. a typical project will have between 20 and 200 versions. i delete all but the final 5 or 10 to save disc space.
then while you're saving whatever_xx.fla and flash pro crashes or your computer unexpectedly shutsdown corrupting whatever_xx.fla, you still have the previously saved whatever_xy.fla (where xy=xx-1) that still works. you only lose the work done between the two versions.
kglad has answered the question about the file that failed to save correctly, but you should look in this folder:
C:\Users\New\AppData\Roaming\Adobe\Common\Media Cache Files
In there you may find the latest auto recovery file for the unsaved version of your animation.