Have you started seeing more and more black lines around your sides when you present?
Well with the growth in the audio visual space of the screens that PowerPoint are displayed on there as been a push towards widescreen formats to suit videos and most other forms of media that now fits this audio visual format
So what can you do to fix it?
Well if you are using Office 2013 it automatically starts any new presentation as 16:9 or wide screen so you don’t need to do anything but if you are using an older version or want to fix a current presentation to suit the new audio visual screen then follow this knowledge article on from Microsoft
Make it wide screen and take you PowerPoint into the new world of screens