Windows Movie Maker was discontinued in January of this year. A zombie imposter has risen to the top of the Google search results though. This is not a legitimate program and is actually fake software filled with spam ads.
Do not fall for this fake program!
Victims that download the fake Windows Movie Maker do get Microsoft's video editor, but are blocked from features like saving files unless they pay for the "full version." This "upgrade" costs $29.95, despite the fact that Windows Movie Maker was free when it was available.
When looking up programs to install you can cross reference that the site is legitimate by using Bing.