This new webcam, is it a usb webcam? What make and model webcam is it?  Have you disable the onboard webcam of the laptop? What OS came preinstalled with this laptop? Did you upgrade or clean install windows 8? Do you have the correct OS bit drive for the webcam...eg 32 bit driver or 64 bit driver, it makes a difference?
Some older webcams will not work with windows 8. I have one old web came that will work with XP, Vista but wont work with windows 7 or windows 8.