Very loud noise in headphones

Hi
When trying to play back music I get a very loud humming noise in my headphones. Its almost impossible to hear the music, never mind the beat with the squealing humming noise. I've reset up the program after the best part of a year away & it used to work okay before.
Any help would be really appreciated
Cheers
When trying to play back music I get a very loud humming noise in my headphones. Its almost impossible to hear the music, never mind the beat with the squealing humming noise. I've reset up the program after the best part of a year away & it used to work okay before.
Any help would be really appreciated
Cheers