Hi Pasquale,I believe the autosave file will have been deleted when you selected 'No'. This would be by design so that your disk doesn't get full of redundant, unused autosave files.
You can look, though, as the autosave file will have a .s99 extension and, if it exists, it will be found under Program Files in the Stardraw AV installation folder, or in the folder that you last saved the .s01 file into.
If you find it, just change the extension to .s01 and open as normal.
Good luck.