Cubase 7.5 Elements can't find Impulse 49 Midi Keyboard

Hey, I just recently purchased a copy of cubase 7.5 for PC and a Novation Impulse 49 Keyboard. When I installed everything it all worked with no problems at first, but after a few days, Cubase can no longer find the midi keyboard. I have tried reinstalling everything and the keyboard has no problems as it works on my brothers PC. Im now lost and could not find any help around the net. Any help would be greatly appreciated.
Thanks :smiley: