I am not getting-at-you, but you have been coming to the Help forum long enough now to know that you should give as much information as possible about your set-up, this of course would help those offering assistance to you! You should always do this when requesting help, no matter what the problem is.
In this instance, what is make of mouse and is it wired/battery/wireless? What is your Sound system make-up? Is PC desktop or laptop - make/model?
Have you tried anything on your own to sort the problem and if so what have you tried?
Have you tried first-line-of-defence - i.e. System Restore, back to when it was all working fine?