IF you did, go in on the unopened file and return its type to what it was and it should open fine.
Photoshop stores the files it is working on in a temporary folder on your computer. You can probably your repair psd file, although it might require a little digging to do so.
1. Open "My Computer" from your desktop. Double-click your hard drive.
2. Open "Documents and Settings."
3. Open the folder labeled with your user name.
4. Open "Local Settings" followed by "Temp."
5. Scroll down to the files beginning with "Photoshop" ("PS" for older Photoshop CS builds). This will be followed by a series of letters and numbers.
6. Double-click each "Photoshop" ("PS") temp file to open them in Photoshop CS. This is the only way to identify which temp file contains the project you wish to recover. Luckily, because when Photoshop shuts properly it deletes its temp files, there should be no more than three or four.7. Select "Save As" from the "File" menu when you find the temp file you want. This will make the file permanent.