[Return to Windows Media Player: LSU Overview]
In order to rotate a video, you have to use Windows Movie Maker.
-- Click here to download Movie Maker from Microsoft.
1. Open Windows Movie Maker. click Add Videos and Photos to add the videos.
2. After adding your videos, click on the video on the right.
3. Once the video is highlighted, click Rotate Left or Rotate Right in the Editing block in the Home tab.
Referenced from: Microsoft