A. Hardware [computer equipment or machinery]

personal computer / PC / desktop computer: a computer that fits on a desk, used by individuals at work or at home
laptop (computer): a lightweight portable computer that usually fits in a briefcase
tablet: a portable personal computer operated by a touch screen
hard disk: a device [piece of equipment] inside a computer that stores large amounts of information
disk drive: a device that allows information to be read from a disk
scanner: device for transferring pictures and texts into a computer
memory stick: a small device that lets you carry computer data anywhere conveniently; you can then plug the stick into any machine
RAM (random access memory / memory): the memory available on a computer to store and use information temporarily; can be measured in gigabytes
(micro) chip: a very small piece of semiconductor, especially in a computer, that contains extremely small electronic circuits and devices, and can perform particular operations
network: when a number of computers, for example in one office, are connected together (or networked) so that they can share information

B. Software [computer programs that you install]

application: a piece of software designed for a specific purpose. This is often shortened to app.
word-processing: writing and storing printed text on a computer
spreadsheet (program): a program, or the grid you create with it, to perform mathematical operations
database: a large amount of information stored in a computer system in such a way that it can be easily looked at or changed
(computer) graphics: pictures, images and symbols that you can form on a computer
virus: hidden instructions in a program designed to destroy information
display: what you see on the screen of an electronic device
A computer shows a range of icons on its display. You put the cursor on the one you want to use and click on it to open it.

You probably store a lot of important information on your computer. So, it’s sensible to back up all your files on a regular basis. Then it’ll be less of a problem if you delete something accidentally or if your computer crashes.
A particularly useful feature of most applications is the one that allows you to undo what you have just done – just click on Undo and it’s quick and easy to correct anything that you have keyed in by mistake.
After a few years you may want to upgrade your computer as they are always developing machines which are faster and more powerful. If you don’t do this you may not be able to run all the software you need. You can usually download upgrades to your computer’s operating system or to your applications from company websites.