If the photo viewer that you're using ignores the orientation tag stored in the photo's Exif data, then your photos will not be displayed in the correct orientation.
Windows 7, its default applications such as
Windows Photo Viewer and
Windows Explorer ignore the Exif Orientation tag. Use another app that can read this tag so that your photos will appear in the correct orientation.
Windows 8 and later versions, the default photo viewer and File Explorer can support reading the Exif Orientation tag and will display photos properly.