I'm guessing up upgraded Windows 7 ?
Use any of the following methods below:
Go to the Device Manager on your computer
Click on the Webcam option that is displayed in the list.
Right click on it and choose Update Driver Software from the options that are available.
VAIO Update Software. Use the driver update software "VAIO update" from the link below:http://www.sony-asia.com/support/product/VGN-CR343N