Verified answer

Most people view powering down the computer as a judgment call, it depends what your goals are. I'll outline some of the reasons you may or may not want to turn the computer off when shutting it down

1. Turning off not harmful --people used to think flipping the power switch on and off was a bad idea. This is not true.

"Contrary to popular belief, turning on and off the computer doesn’t shorten its life. As Lawrence Berkeley National Laboratory points out, "The belief that frequent shutdowns [of PCs] are harmful persists from the days when hard disks did not automatically park their heads when shut off; frequent on-off cycling could damage such hard disks." Lawrence Berkeley reassures us that, "Modern hard disks are not significantly affected by frequent shut-downs. Shutting down computers at night and on weekends saves significant energy without affecting the performance." So, if you are going to be away from the computer for several hours, turn it off."

http://www.nesea.org/buildings/info/eleventhings.h...

an alternative viewpoint is here:

http://www.smartcomputing.com/editorial/article.as...

2. RAM

Turning your computer off gives your Random Access Memory a chance to unfragment

"The memory (RAM) becomes fragmented with use. As you open and close your favorite programs, little bits and pieces of your program stay in RAM and are not completely eliminated when you close them. Eventually, your 64 Megabytes (or whatever) of RAM becomes so "chopped up" that you cannot open large programs or data files anymore, or they open very slowly. We've seen computers that took about 30 seconds to a minute to respond to the click of a mouse button. This delay time would drop to about 2-3 seconds upon restarting the computer. When you restart your computer, the RAM is loaded a few of the small programs that automatically start when you turn on your computer. (You can see some of their icons in the System Tray next to the Time in the lower right-hand corner of the screen.) The rest of the RAM is free in a large, continuous block, allowing you to load more of your important programs."

3. the components get a chance to cool down

This is a double-edged sword because some people argue that the heating and cooling cycles slightly weaken the connections between components (which is not true !!!) and so argue that the change it temperatures is more important than the high temperatures.

4. Saving energy -- you didn't mention if you had a laptop or a

desktop machine, but turning off even just the monitor of a desktop machine can significantly save energy

"If a computer must be left on after-hours, turning off the monitor will not affect the program that is running, but will save 75 per cent of the total energy required to run the computer. These savings can be compounded. Shutting down computers when not needed reduces heat generation.

Hope this helps.

Turning on and off will make the computer unstable and in long term memory chips will fail. so its better to keep it running than switching on and off.

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