Hello. Thank you for contacting Just Answer.
What happens when you try to play a movie from Netflix? Do you see video? Is there no audio at all?
What are the specifications of your PC (Windows Xp, Vista, 7?)
What browser are you using?
What video card do you have?
What Sound device do you have?
From what I understand, you do need Silverlight to play Netflix. You can download and install it from here:
Once installed, try Netflix again.