Windows Movie Maker is a terrible program for anyone seriously considering making a professional video. It is buggy and crashes a lot, even on good computers.

However! It is quite a good free tool for the novice movie maker (as long as you save your work every 2 minutes in case it crashes!). It is a very easy program to use and actually has more feautres than first meets the eye. I'll go through the main features.

Features
-Allows you to merge video, images and audio.
-Allows you to add "special effects" to video, images and audio.
-Contains many different transitions, to allow you to change from clip ti clip smoothly.
-You can add Titles, Credits and Notes over your footage or on seperate backgrounds.
-You can save as many file types, including some suitable for large video sharing websites such as Youtube.

To be perfectly honest, novices would be better off using the better made VideoSpirit Pro, another free movie making program for download, it crashes a lot less and has more features. If you don't wish to download anything, and Movie Maker is on your computer, then it is ok for the novice.