Computer Guide

Should I turn my computer off or leave it running?
by George Skarbek - 11th July 2006

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Q: Some days I use my computer in the morning and then leave it for a few hours before using it again in the afternoon. Should I turn it off or leave it running?

A: There is no definitive answer. Generally I use and recommend the use of power saving, especially for the CRT monitor, mainly to save electricity. If the computer will not be used for many hours, and especially overnight, I believe it is best to turn it off.

It is true that constant switching on and off is damaging for computers because of the heating and cooling cycles and is sightly harmful for the hard disk. Many people find that leaving them on saves time by not having to wait for the computer to start and load all the software required, and at the workplace this extra time must be factored in. Some companies even leave the computers on overnight.

All relatively new hard disks are designed to withstand this cycling and save about 80 per cent of energy when in the low-power mode. Typical hard disk designs are for 30,000 to 50,000 cycles. This covers computer usage for eight hours a day, 250 work days a year, over four years, with the drive spinning down every 20 minutes.

However, when a computer is left switched on and the hard disk keeps spinning, it rapidly wears out the bearings and consumes electricity. It also makes it easier for anyone else to quickly use the computer. This may be an advantage or a security problem for you.

Power consumption of a computer varies with the design, memory, number of hard disks and additional cards, but about 150 watts is a typical figure. An average CRT monitor also uses about 100 watts, with LCD monitors consuming about 30 watts.

For those who like to leave it on, energy management is now available on all new desktop computers, and when enabled can virtually put your computer to sleep when it's not being used and reducing the monitor's power consumption to less than 10 watts. Reducing the computer's power consumption to a few watts by stopping the disks from spinning also reduces wear on them. They wake up at the touch of a keystroke or a mouse movement, and with such a set-up I would leave the computer on for several hours unattended during the day.

Do whatever you feel comfortable with. There are benefits in both methods, especially with energy-saving computers and monitors.

Q: A Microsoft feature has been annoying me. In MS Word, if I type 2006 and immediately follow this with Enter, MS changes 2006 to 2006-06-20 (today's date). How do I tell the program not to do this? I have looked in Tools, AutoCorrect Options, Customize and Options, but I can't spot a likely button to tick or untick.

A: With me this is a love/hate relationship. I find this feature of use and have added some of my auto complete entries, but at times I am also annoyed by Microsoft trying to be helpful. Although I am not quite a touch typist, I do look a lot on the screen and can spot the unhelpful suggestions, including the date.

To turn this feature off, you have to start in the Insert menu, which is not intuitive. After clicking on Insert, select AutoText and remove the tick from Show AutoComplete suggestions check box.

Q: I am frequently unable to download attachments to emails on Outlook Express. I am using Windows ME and have been advised by a retailer that I should upgrade to Windows XP to fix the problem. Is this a likely cure? Or should I buy Microsoft Word - the absence of which in my software has also been suggested as the cause of the problem?

A: There is no need to upgrade to XP nor to buy Word, because this will not make a difference to OE attachments. There is a free Word viewer available from the MS site so you can view, but not edit, Word files. This can be downloaded from  .

To determine which program is needed to open the attachment, you can ask the sender to let you know, or look up the program(s) associated with a file extension on


To look at the e-book in PDF format, Computer Guide, based on these columns click here