Promethean activeboard 300 resolution

Hello!

We have some promethean activeboard 300's but their resolution seems to be off. When we draw circle on the board it is eliptical.
What resolution does the PC and projector need to be? I.e. the projector has setting such as Fill, Letterbox, 16:9 and 4:3

What a muppet lol, can some kind soul move this to the Promethean forum. :o

EDIT:

Thankyou!

Anyone? I'll even accept answers in the form of a song or riddle. :p