Desktop A desktop computer is basically a computer which is not portable. You can use the desktop to use the internet, send emails also you can do your work on there with a program called word. A desktop works with a computer base unit attached to it, without it the Desktop cannot work.
Laptop The purpose of a laptop is that it can do everything a Desktop can do, but the biggest difference is that a laptop is portable. Laptops are much smaller than a desktop and is lightweight and easy to move.
Tablet A tablet is exactly like a laptop but this is touch screen. You can use a pen to control it instead of your fingers all the time. This is even easier to move about and is lightweight. There is no keyboard or mouse attached to it.
Computer Base Unit The computer base unit usually comes with the desktop computer. The base unit holds in all the components e.g. A motherboard, CPU, heatsink and all the other important components.
Games Console Games consoles are mostly used to play games against your mates and people around the world. A games console has internet to connect to play other people. You can get portable or a not portable games console.
Mobile There are two types of mobile phones now days which are, IOS and a android. Mobile phones are portable devices which can communicate with other people all around the world. You can send a message, phone them or you can even go on the internet and email them.
PDA A PDA is computer that fits into your hand, known as a palmtop. It can store a lot of things e.g. numbers, addresses it can access the internet, play games etc. Its so small that you can just put it in your pocket and walk about with it. it is a good tool to stay organized.
Server Servers are basically a computer that "serves" information to other computers in a network.