|If you keep hearing the "device connected" then "device disconnected" sound, it is most likely because there is not enough sustained power through the USB port to drive the webcam.|
You can fix that by buying a mains-powered USB hub. Plug the hub in to a mains socket (with the supplied mains adapter) then plug the hub in to a USB port on your PC.
Now plug the webcam in to one of the hub's USB ports.
Mains-powered USB hubs at Amazon UK:
At Amazon USA:
Be sure to buy a mains-powered hub, not a plain hub which can't be plugged in to a mains socket.
message edited by phil22