Webcam not working

Hi
Forgive me for posting, I have searched but not found the exact problem we have. My daughter has an Aspire One running Linux. We had to restore it to factory settings when it stopped working last month. Once that was done we did the live update as directed by Acer. Since then the webcam isn't working at all. When she is in messenger she gets the following message when someone starts a call with her:

You have answered the video call.
Your microphone or webcam may be busy or not ready. Please check that they are usable and try again. If this doesn't work, the problem may be with your IM server.

When she tries to start a video call she gets:

You have accepted the invitation to start sending your webcam.
Your microphone or webcam may be busy or not ready. Please check that they are usable and try again. If this doesn't work, the problem may be with your IM server.

Can anyone throw any light on this? We'd be very grateful.
Thanks
Nessie