Why do we need them?
What is a Driver?
A Diver is a piece of software the let's the O.S. (Operating System) communicate with the hardware installed in your computer. Many OS come with default Drivers so you can use your computer to get the latest and greatest Drivers.
What Drivers are required for basic systems?
The computer parts that require a Driver are the:
RAID array (If the feature is available)
USB 3.0 (If case supports it)
Where do I download Drivers?
Pre-built computers with an OS will have the Drivers required for your hardware pre-installed. But if you are building a computer yourself then you will need to install the appropriate Drivers after you install the OS. These can be downloaded from your hardware manufacturers website. Your hardware will include a DVD of the earliest Drivers. If you don't have a functioning computer this DVD can be used to install the LAN/NIC Driver to download the other Drivers and then update the LAN/NIC Driver.