Go to the logitech website, on the home page you should get the list of countries, (click on the country, you are)
Then click on the customer support tabs, products (webcam) , Seach by image......find out the model you have and go to the download drivers section.
You can go to logitech support website, choose your OS and download the software you need : http://www.logitech.com/...
Best regards