Hard Drive-  Is a data storage device used for storing and retrieving  information using rapidly rotating disks coated with magnetic material. An HDD retains its data even when powered off.

CD ROM- A compact disk that functions as read-only memory.

RAM (Memory)- Random access memory (RAM) is the best known form of computer memory. RAM is considered "random access" because you can access any memory.

Flash Drive- A small electronic device containing flash memory that is used for storing data or transferring it to or from a computer, digital camera, etc.

Router- a power tool with a shaped cutter, used in carpentry for making grooves for joints, decorative moldings, etc.

Modem (cable)- A device that connects one or more users to the Internet. It combines the modem, which accesses the ISP, and a router, which forwards traffic to the modem and distributes responses to the requesting.

Modem (DSL)- Short for asymmetric digital subscriber line, A DSL is a type of DSL broadband ...copper telephone lines (POTS), when compared to traditional modem lines.

Modem (Dial Up)- The definition of Dial-up defined and explained in simple language. ...When a user initiates a dial-up connection.

Three Operating Systems 

Linux And Unix- Is a Unix-like computer ... The defining component of Linux is the Linux kernel, an operating system.

Windows 7- Windows 7 is the latest release of Microsoft Windows, a series of operating systems produced by Microsoft for use on personal computers, including home and business desktops, laptops, netbooks, tablet PCs 

Mac OS- Mac OS is the trademark-protected name for a series of graphical user interface-based operating systems developed by Apple Inc. (formerly Apple Computer, Inc.) for their Macintosh line of computer systems.