A driver is software that communicates with the hardware and operating system of your machine (in a nutshell).
Your motherboard should come with a cd of drivers specifically for it. Also if you add something like a video card, it should come with (or you can download from the video card's manufacturer website) a driver for your operating system.
Yes, when you install Windows 7 you can use the cd your motherboard came with to install the drivers for your network card (which will allow you to get online). Then you can install any other drives that are on that cd. Once connected to the internet, you can use Windows Updates, which will pickup any other hardware drivers that are needed.