Dont have instalation cd for logitach webcam

Hello,
i have a logitech webcam but no software to properly install it the serial number is (to the best of my sights ability to read it) is LZ414608248 i do not know the model name other than it is from logitech it has auoi light adjust feature do not know how old it is it was given to me by a friend can you help me find the right software to proper install this hardware so i can use it
kathy