Absolute Beginners Guide to Upgrading and Fixing Your PC

It's a funny name, but a necessary device.

A computer mouse is a small handheld device. Most mice consist of an oblong case with a roller underneath and two or three buttons on top or along the sides. When you move the mouse along a desktop, an onscreen pointer (called a cursor) moves in response. When you click (press and release) a mouse button, this motion initiates an action in your program.

Mice come in all shapes and sizes. Some have wires, and some are wireless. Some are relatively oval in shape, and others are all curvy to better fit in the palm of your hand. Some have the typical roller ball underneath, and others use an optical sensor to determine where and how much you're rolling. Some even have extra buttons that can be programmed for specific functions or a scroll wheel you can use to scroll through long documents or Web pages.

Of course, a mouse is just one type of input device you can hook up to your PC. Trackballs, joysticks, game controllers, and pen pads all count as input devices, whether they work in conjunction with a mouse or replace it. You can use one of these alternative devices to replace your original mouse or (in some cases) to supplement it.

If you have a portable PC, you don't have a separate mouse, but rather a built-in pointing device of some sort a touchpad, rollerball, or track stick (the thing that looks like a little rubber eraser). Fortunately, you don't have to use the built-in pointing device on a portable PC; most portables let you attach an external mouse, which then overrides the internal device.

Just as with the keyboard, the most common mouse problems result from loose connections. These usually occur when the mouse somehow becomes unplugged from the computer (such as when you tug too hard on it or accidentally roll it off the desk). Because the mouse is a mechanical device, its roller ball can eventually wear out with use, making cursor movement difficult. The constant movement of the mouse across a desk surface can often damage the mouse cable, too. If your mouse's behavior becomes too erratic, it might be time to either clean or replace the little rodent.

If you have more than one input device connected to your computer a mouse and a joystick, for example these two devices can sometimes interfere with one another. I've seen instances where changing the settings on a joystick affected the behavior of a mouse. Always look for unwanted interaction when you have two similar devices connected to one PC.