Joe's Quicktime movie files were playing sideways on Windows 7. He upgraded to Windows 10 and now it plays properly. Leo says it's likely that the video was shot on a mobile phone in portait mode and the previous version of windows couldn't read the metadata for the accelerometer in the phone. Now, with Windows 10, it can read that data and adjust the image properly. If it happens again, Leo suggests using VLC Media Player to rotate it.