Have you revived your VX-700? Share your results in the comments below. If all else fails, check the USB cable for breaks—the VX-700 is known for fraying cables near the webcam hinge. A simple re-solder or replacement of the USB cable often brings a "driverless" camera back to life.
Download and Install Drivers for the Microsoft LifeCam VX-700 Download Driver Camera Web Microsoft Lifecam Vx 700