The mother board will generally be the largest circuit board and will be lying flat on the bottom of a desktop computer. Also a small rodent whose shape and tail inspired the folks at Xerox's Palo Alto Research Center who invented the nifty device. Not all mice are created equal. Some are more ergonomically-designed than others. You can also use other devices if you have limitations that make using a mouse difficult.
Laptops often use trackballs and touch pads to save space.
Trackballs and touch pads are available on special keyboards for persons with disabilities or just looking for more comfort. Top of Page N Networ k - connections among several computers so that the machines can share printers, files and other equipment. They may also be connected to a server computer and share software. Operating System - the list of instructions that teaches a computer how to operate its disk drives, printer, keyboard, mouse, monitors, etc. Many are available on the Internet.