Sorry, but this forum is for introducing yourself if you're a new scratcher. Try asking again in the Questions About Scratch forum, you might get a better response there.
I don't think you can put the .sb files in Movie Maker (I assume you're talking about Windows Movie Maker, correct?).
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.sb files are files that contain images (sprites,) scripts, and sounds. A video file is a sequence of images. See the difference?
The only way that you can import SBs into WMM is to record it with a screen capture software, such as Camstudio, which I recommend.
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SciTecCf has the answer here...you can use a screen capture product like Camstudio to capture a portion of your computer screen to a movie file. Then, just setup the area that it captures to be the stage area of Scratch and run your Scratch project. Hope that helps
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