Blender 2.58 won't open my saved files.

Hi Blender,
I uploaded Blender 2.58 to my computer and modeled a mansion, saved the file, and titled it, “Mymansion”. Then I exited out of the program. I opened the program again, hit open, and hit mymansion toedit it, but when I hit the file, the screen closed and went to the default and a little box showed up on the corner of the screen that read,

"ERROR: File Format is not supported in file:“C:/Mymansion.blend”

Any suggestions on how this can be fixed?

Thanks

It’s possible your save file is corrupted and you may be out of luck.

One thing you can try is to append the file,… it may be possible to bring in some things from the file even if the whole thing won’t open.

also, look at “recover auto save” and “recover last session”, but it may be too late for those