There are several reasons why your video is sideways on Windows Media Player. For example, older versions of the app can’t support videos recorded in landscape mode. You can try reinstalling Windows Media Player to get the latest updates. Here’s how to do it: 1. Type “Features” in the search dialog box. Click Turn Windows features on or off. 2. A small pop-up window will appear. Locate Media Features and check the box to open a drop-down list. 3. Remove the checkmark from the box next to Windows Media Player. 4. Go back to Start and restart your computer. 5. Re-open the Turn Windows features on or off control panel, go to Media Features and expand. This time, check the Windows Media Player box and click OK. 7. Restart your PC one last time. However, sometimes the problem is caused by the latest Windows update. Here’s how to check if that’s the case: 1. Write “system restore” in the search dialog box. Click on Create a restore point to open the System Properties window. 2. Then, click System Restore. 3. A new pop-up window will appear. Click Next to open a list of restore points. Select the update you think caused the problem and click Next. 4. Wait until the system restore is complete. It can take several minutes. 5. After it’s done, re-open Windows Movie Player to check if the video is functioning properly.