You have finally decided to go and either upgrade or replace your ancient computer or buy a brand spanking new one. That's the first step. It is very important to learn the basics of computers before you go and buy one or start to learn what to look for. Let's figure out what you'll be using this computer for and who will be using it. Just like a car, you need to know what you'll be using this computer for.
Kids are into games, the Internet, printing cards and other memory and graphics intensive things.
If so, you might want to try out online games, which are also intensive on memory, your processor and your video card. And of course, you will want to dip your toe into the big ocean known as the Internet. That puts a big strain on your computer as a whole. That is only just a little bit of what you can accomplish with your new computer.