The taskbar shows all of the applications and windows that are running on your computer at any given time. Most people keep their taskbars across the bottom of their computer, but it's possible to move it to any edge of your computer screen. It's also possible to have it disappear when not in use. This is strictly a matter of preference. Keep in mind that the task bar is the entire gray strip in the figure below all the way from the START button at the left to the picture of the two computer monitors at the right.

In order to activate an application that is currently running (but not visible) on your computer, click on the appropriate button on the taskbar. The current application (or window) will always have a button that appears to be pressed down. The other applications will appear to have raised buttons.

It is possible to have many, many, many windows open at the same time. As you open more and more windows, you will see less and less of each description on the taskbar. One way to see which window will open when you press a button is to let the pointer hover over it for a second. Be sure to hold the pointer still. A small box will appear with a description or, if it is a web page, the title of the web page.