Dell inspiron n5520 drivers

#1
I have a new Dell Inspiron 5520, I had changed the operating system to Windows 7 from Ubuntu, after which some of the drivers were not installed. I now need the drivers to things like the webcam, function buttons etc, so need help form forum members to let me know where I can get the drivers from.
Specifications of my device are:

i5
500GB hard drive
4GB RAM and
1GB GC