If you don't remember the name of the file you lost, but remember approximately 'when' you created it then try this technique

1. Click on Start à Find à Files or Folders
2. Click on the Date tab
3. Click on the between option
4. Choose a date range, in the boxes provided
5. Click on Find now

NOTE: Make sure that you haven’t entered anything in on the first tab in the “named” box and the “Look in” box should say “My Computer” with the Include Subfolders box checked.

NOTE ALSO: When you find your file, before opening it, make a note of where it is saved by looking at its location in the In Folder column.