You need to go to dell.com/support and input your service tag of your pc, then it will show you all the drivers you need for your PC.
You will need:
Lan, WiFi, Audio, Chipset, VGA (Graphics Card) drivers, and your particular laptop may also need USB 3.0, SD card, or Bluetooth drivers as well.
When you load a standard install of windows onto a computer, you have to download and install all of the hardware specific drivers; this is just already done for you on the factory included operating system.