Computers are made up of HARDWARE and SOFTWARE.
The physical parts of a computer make up the hardware. Inside the computers CASE you will find hardware like the MOTHER BOARD, MEMORY, CPU and a HARD DRIVE. To get data into the computer you may have a KEYBOARD, MOUSE, FLOPPY DRIVE and a CDROM DRIVE. For communication you may have a MODEM. The modem can be inside the case or outside. If outside it will be attached to a SERIAL PORT. You may also have a PRINTER attached to your computers PARALLEL PORT.
The main software for a computer is the OPERATING SYSTEM. This software is what makes your computer start and keeps all of the hardware pieces talking to you and each other. On top of that you may load your various APPLICATIONS. Typical applications include a WORD PROCESSOR or maybe a SPREAD SHEET program. Very popular these days are BROWSER and EMAIL programs which are used to access the INTERNET. There are many different types of software for both fun and business use.