That's too bad. Do you do backup archiving? (Go to File, then Backup/Restore). You can create a backup archive to put on a disc or email to yourself or whatever, and if everything is lost or if something gets messed up, you can restore everything like it was when you created the archive. (I also do it so I can put it all onto a second computer if my first one dies for some reason.) I do archiving about once a week and I email the file to myself. The process of creating an archive stops all backtesting though, so make sure you don't do it while you're in the middle of something important. If your computer has been doing backups automatically, you might try to restore a recent one, and that should have all of your strategy files as they were. (I'm posting on this on the blog so that others can benefit from it if things go wrong.)