Device drivers are instruction sets that tell the computer hardware when, how, and why to work. They are responsible with everything that control the behavior of your personal computer.
Device drivers is a term known just on personal computers (unix/linux/bsd & windows running machines). There are no device drivers on Mac OS X (well, they exist, but they are called KEXTs).
When you buy a new laptop or computer, if it has the operating system installed, usually the distributors also installed the drivers, so you could just run everything flawlessly. If you have installed a fresh copy of an operating system, then most of them won't be installed, so sound, videos and usb devices may not work properly or may not work at all. However, if you have reinstalled the operating system or bought a new computer and it lacks it's drivers, read further and you will get information on where to find drivers for your hardware.
You must keep in mind that drivers are produced based on the specific model of a hardware, this means that a driver from the company “X” won't work for all the “X” boards. You have to know the exact model of your board/hardware so that you'll be able to install the correct drivers.
Another thing that you should keep in mind, is if you are running a linux system which is not Ubuntu or something as user friendly as Ubuntu is. The problem is that in linux, you need to browse the source code, install some compilers and libraries, and then compile the source code in order to make your drivers. This is an advanced, and more complex process, and I'm not familiar with it, so I won't talk about this.
If you are running Windows 95 – Windows XP:
– One method of finding drivers is by going into Control Panel → Add New Device → Automatically search drivers and software on the internet
An alternative method (and the most recommended one) is by using the company and model of your hardware/board to search it on the internet and to get the latest official releases.
The last (and most simple) method is by using the software and driver cds that you have received. However, not all the new computers come with driver cds.
If you are running Windows Vista – Windows 7:
1. Go to Control Panel → Automatic Updates → Turn It on
2. Go to Control Panel → Add New Device → Search on the internet and Microsoft Driver Database
This being said, I hope that you will be able to install all the drivers that you are missing.