I've had a couple of members of staff come to me with a disc full of Powerpoints that they want to teach with, but when they view the powerpoints, they show up black...
Which isn't helpful when the text is in black also, when I open the powerpoints on my computer they appear normal and have white backgrounds...

Is there a setting somewhere in Office/Powerpoint that changes the default background colour when viewing a presentation?
I know that the computers the staff are using won't be up to spec to run a newer version of Office... And at the moment I don't have the budget to get some new ones...