I did a fresh install of Ubuntu 12.04 LTS on my Compaq Presario C700. I've had previous versions installed, starting with 9.10, but startup speed was slow so I decided to back everything up and re-create the partitions.
Every time I boot the system into the login screen, the webcam turns on, stays on for a few seconds, then turns off. It does the exact same thing everytime I launch Shotwell. I've also seen it come on at random times as I've used the computer. I'm starting to get a little paranoid, and would appreciate any help in identifying the cause of this behaviour.
dmesg | grep cam
and see if it outputs anything. If it outputs anything useful please include it in your question.