A computer is made up of several main parts. obviously,the most important is the CPU, or central processing unit. this is the part that house the computer memory and processing chip, in other word, the computer is brain. Most cpu now have a cd and/or dvd burner, that is, a device for recording onto a cd or dvd already built into the unit. they also have usb ports, that is to say, sockets where you plug in other device, e.g. your scanner or memory stick. most cpus have software,i.e. computer programs,already loaded when you buy the computer, but many people like to add other program to personalize their computer. Other necessary parts of any comouter system are the monitor or screen,the mouse,and the keyboard.