I'm not sure why a power outage would have caused this, but I'm assuming a file has been corrupted. What I'd like for you to do, however, is to check to see if your folder settings have been altered.
Navigate to the 'Start Menu', and type in 'Folder Options'. Hit 'Enter'. Click on the button that says 'Restore Defaults'. Also, you can navigate to the 'View' tab and hit 'Restore Folders' and press 'Yes'. Check any boxes that you would like to have as your default settings. Then, reboot your computer and check to see if you're still experiencing this problem. If you are, let me know and we'll work on another fix.