Windows Movie Maker for Windows 7 comes with the Windows Live Essentials package. It lets you create movies from audio files, videos, pictures and captions and lets you save movies to your computer and publish them online. When you create a new movie project, Movie Maker maintains a list of recently used projects in its history, which allows you to reopen the project the next time you open Movie Maker. Although Movie Maker doesn't have an option to delete this history, you can clear the history from the Windows registry.
Close Windows Movie Maker if you have it open. Click "Start," type "Run" in the Windows search box and press "Enter." Type "regedit" in the "Run" box and press "Enter." Type your Windows administrator password if prompted.
Double-click the "HKEY_CURRENT_USER" folder in the left pane, then double-click "Software," "Microsoft," "Windows Live" and "Movie Maker."
Click the "Recent" folder under "Movie Maker" in the left pane. The right pane displays entries for the history items, labels them in capital letters starting with "A" and displays the history item's path under the "Data" column.
Right-click the history item you want to delete, then click "Delete." Click "Yes" on the "Confirm Value Delete" prompt. The item will no longer appear in the "Recent Projects" history in Movie Maker.
Clearing the history doesn't delete any of your Movie Maker project files or videos. To remove these items, open the folder where you saved the project or video, then right-click the item and select "Delete."