Given the huge amount of information that you didn't give us, like which program and version, source of the files and how filmed, in Movie Edit Pro, select the video clip on the timeline, Effects tab, View/Animation, rotation, and click on the rotate button twice.
If you're using Vegas, you are in the wrong forum. See the sticky at the top of this forum.
Are these clips from a phone? If so try using your phone so that the power connector end is to your right when recording either from the front or rear camera. (power and volume buttons to the top of screen).