Go to device manager, look for "imaging devices", if its not there, then the camera is faulty and needs replacement. If it is there, then reinstall the camera driver using the acer erecovery management.
Please join me in congratulating IronFly who is the first Acer Community Member to achieve the rank of ACE Pathfinder. IronFly has shown a consistent willingness to help others and has worked hard to earn this new Rank. Congrats and Thank You IronFly.