Hardware & Software
The difference between them
Computer hardware is the physical components that make up the computer system. Hardware is useless without software to run on it. Software is instructions that tell computer hardware what to do. Software is useless unless there is hardware to run it on. For a computer system to be useful it has to consist of both hardware and software.
Hardware
Hardware is the physical parts of the computer system - the parts that you can touch and see. A motherboard, a CPU, a keyboard and a monitor are all items of hardware.
Software
Software is a collection of instructions that can be 'run' on a computer. These instructions tell the computer what to do. Software is not a physical thing (but it can of course be stored on a physical medium such as a CD-ROM), it is just a bunch of codes. An operating system such as Windows XP or Mac OS X, applications such as Microsoft Word, and the instructions that control a robot are all examples of software.