To Rotate a video means to change from portrait (vertical) to landscape (horizontal) or vice versa.
Open PowerDirector on your desktop and follow these steps:
Add the video you would like to rotate to the Editing Timeline.
Click on Tools, then Crop/Zoom/Pan from the drop-down menu.
Use the arrow keys under Rotation to gradually rotate your video, or type in 90 to switch the orientation by 90 degrees.
Click OK when done.
For more information, check out How to Rotate a Video on Windows and Mac for Free.