First make sure that the type of files you are attempting to load into Movie Maker are supported see this list here
Windows Live Movie Maker Help Center - File Types
There may be some additional information contained in the Event Viewer (Windows Logs, Application), you might look there for errors regarding app hang or app crash for more information.
Finally you might try using the applications and features applet in the control panel to either Repair (try that first) or Uninstall, Windows Live Essentials and then try re-installing (make sure you have backed up and or saved (to a safe location) any previous projects and or files that have been created with any of the Components of
Link Removed.