The hard drive is the device that stores data even when it isn't powered. This allows the user to turn off the computer and maintain the data and computer settings.
Computer information, such as the amount that can be stored on a hard drive, is measured in bytes.
Memory, also called Random Access Memory or RAM, is a form of data storage, and is the computer’s short-term memory. This short-term memory disappears when the computer is turned off. If you're working on a document, spreadsheet, or other type of file, you'll need to save it to the hard drive to avoid losing it.
The Processor, also called the Central Processing Unit or CPU, is the computer's brain. Its job is to carry out commands. Whenever you press a key, click the mouse, or start an application, you're sending instructions to the CPU.
Ports are the outlets on the computer which are used to connect external devices such as the keyboard, mouse, or a flash drive.