Resolution: This is a common issue faced due to outdated codecs. Update your computer to the latest audio/video codecs for your operating system, and you should be fine
Resolution: Import your movie files using Handbrake, a free software found here – http://handbrake.fr/downloads.php
If you are not using Windows 7 and above, then it is possible that you are using an older version of Windows Movie Maker. The videos that we have are tested on Windows 7 and Movie Maker Live (which is not compatible with operating systems older than Windows 7). What you should do is convert the MP4 files into WMV format which is natively supported by all versions of Movie Maker.
You can do this by using this free video converter: http://www.freemake.com/free_video_converter/