Drivers, or device drivers, are small programs that basically translate the commands you enter into your computer into a language that the different parts of your computer understand. Every device attached to your computer and every component inside needs its own driver to work. That includes keyboard, graphics card, sound card, printer, scanner, etc. Most drivers come already installed on your computer; others come with a new device that you buy. But usually those pre-installed drivers aren't the best. They are often generic drivers or they were created quickly before the product was actually shipped (and before any potential conflicts or problems were discovered). To ensure that your computer works smoothly, you enjoy all features, and any security holes are closed up, it's a good idea to update your drivers fairly regularly (although another school of thought suggests that you only update if something stops working).
The way to update drivers is to make a list of all your computer components/peripherals, the model number, and the name of the manufacturer. Then go to your computer maker website and see which updates they offer there, click the correct one and download it. Next, go to the individual manufacturer websites to find the drivers that remain on your list. This process can be fairly time consuming and there is some potential for serious mistakes if you install the wrong driver. It's a good idea to set a system restore point for your computer before you start, so you can go back to the original setup if something goes wrong. If all this sounds a little overhwelming, there are some neat commercial programs out there that will take care of the whole process for you in just a couple of minutes. One of the best I've found is RadarSync. You can try it for free at www.radarsync.com