There are four revisions of the M17x. Which one do you have? Did the webcam ever work? What hardware changes did you make prior to the issue? What software changes did you make prior to the issue?
I have an Alienware M17xR4. My webcam was working fine earlier. I made no hardware changes and since today it has stopped working. It is being detected, but displays a blank noisy image and it also passes the Alien Autopsy test. Kindly help me figure out this problem.
Try testmycam.com. Does it look the same in that website? If yes, send me an e-mail to AWSocialMedia@dell.com with your service tag and home address and I'll help you out with the replacement cam.