Reply to traktor 2,mixtrackpro,spotify

Hey guys im tried turnoff computer each time to play 1 of these app!! please help
Im Using Traktor 2 ,windows 8,mixtrackpro mixer,when i play spotify traktor wont find soundcard and play,i turn off everything when i restart and only use traktor than spotify wont find soundcard is says: please check your soundcard,!! its mean sametime 2 appl. sound wont work ore what is this???
Thanks now for your time..
mes