If you could be just a bit more specific, that would really help weed out some variables. There are endless posiibilities, so any little detail would help.
You mention that when you plug the speakers in they act up. Did this just start happening to a setup you have had for awhile? Did you upgrade any components, and afterwards start experienceing problems? Did you install a program and start experiencing problems soon after?
I would love to help, so please, paint me a picture, the more info the better, Thanks.