When you go to a store you see a lot of machines there and they always scare you to death. The first thing you need to know is what you want do with it. If you want just to write some text then a simple computer with one GB of RAM will do fine. If you want a computer for internet you need two GB of RAM. On the other hand if you want a computer for video you need at least 8 GB of RAM and and huge Hard Disk with 1 TB or more. This is necessary because videos are very big, they usually use several GB of space per file.
If you want your computer to be a server you only need a fast processor and RAM. Hard disk is secondary. Keep mind that a server needs special software like Windows Vista Server. Don’t worry because it’s easy to run that program. However unless you know some programming language basic don’t expect to build the next Google this way.
Finally you need a good computer screen. If you are for the laptop you need to make sure the screen it has in it is good enough for you. A good screen will save your eyes and make you work faster, better and longer.
The battery is very important of you plan to travel a lot by plane. They dont have many electric wires there to power you up.
Last but not least you need to keep an eye on the price tag. A very expensive computer usually is not worth the price.