At any given moment, your computer may be checking for keystrokes, saving information, or transferring data. This is done in the background, often without the computer user's knowledge. It is just how the computer operates.

If you happen to press the on-off hardware button to turn off the computer while it is transparently working in the background, files may be damaged, causing future problems. So you should always shut down the computer through the operating system software rather than pushing the hardware button to turn off the computer.

For most Windows computers, that means clicking on the Start button and choosing Shut Down. When the Shut Down Windows screen appears, make sure you answer Shut Down to the question, "What do you want the computer to do?" Then click Okay.

Windows XP users will click on Start, then Turn Computer Off, then Turn Off.

Mac users can shut down properly by clicking on Special-Shut Down.

Windows Vista users will click on the black power-button icon on the bottom left side of the screen, and then choose Shut Down.

Once you complete this shut down process, the software will close all files properly and the hardware will shut off automatically.

There may be times when the computer gets frozen and refuses to respond to any commands. In that case, you may turn the computer off by pressing the on-off button and holding it in for several seconds. There have been times with both PCs and Macs that even the on-off button won't work and the only way to turn the computer off will be to pull the plug. Remember, though, that instances like this should be rare. If you have to press that on-off switch or pull the plug often, it means that the computer has a problem that should be corrected before it gets worse.