If the camera drivers still are not installed or working properly, follow the procedure below to manually install the driver:
Download DroidCam from android market,install it and open it on your phone.Windows® 7 operating system drivers for the built-in Motion Eye® camera are not available on the Sony® eSupport Web site. Connect the phone to your computer via USB (don't select storage mode if the phone asks while connecting USB).
You can use your android as webcam even without wifi by connecting it to your PC via USB. Use your android phone as webcam using USB.