But before you try to defragment your disk, close down any programs you have running in the background. This should include your Screen Saver, which you simply reset to "[None]" by going:

When you have finished defragmenting the disk, repeat the procedure to reset to your favourite Screen Saver.

If you do not close down programs, you will find that the defragmentation program keeps stopping and restarting. This also means that you cannot use your PC while running Disk Defragmenter or it will never finish. Go and have a cup of coffee instead!

Unless you are planning on holding the world to ransom with your computer, you will probably not see a significant advantage between a 1.5GHz machine and an 800Hz one, which is becoming the standard speed for bundled machines nowadays. You would be better spending the difference between the cost of a 1.5GHz machine and an 800Hz by upgrading another aspect of the bundle.

I would strongly recommend that you look at the least-considered, but most used, part of a computer -- the monitor. Many bundled-computer vendors offer some form of upgrade route for monitors from their standard offerings of 15" or, increasingly, 17" screens.

But don't be tempted simply by screen size. Remember, the larger the monitor, the deeper it is at the back. So, if space is at a premium in your study, it is worth considering a flat-panel monitor, although these are expensive at the moment.

Alternatively, look at screens with flat-screen technology. Like the flat-panel monitors, they will give a crisper, more visually friendly, image, but are not nearly so pricey. They do, however, still stick out at the back.

So, you are probably better spending your money on something other than a world-dominating super-fast processor, Dr Blofeld . . . Oh!

Sadly, most computer networks use a combination of username and re-usable password (or PIN) as security for network accounts. The username is rarely a security feature at all. It is usually self-evident if the hacker knows who uses the machine. But you can do something about keeping your password secure.

Don't use a family name, including those of pets, or dates of birth as passwords. These are easy to guess or to find out by so-called "Social Engineering", simply chatting about personal matters over coffee.

But you have my sympathy because the fault for poor security usually lies at the system-administrator level. In an effort to make the system more secure they require you to change your password regularly. When you first log on you probably follow the instruction to use a password which exceeds the minimum character length and which is made up of a combination of numbers and upper- and lower-case letters.

But as time goes on, and you are repeatedly being asked to assign a new password to your account, you slip -- I believe understandably -- into easier-to-remember passwords, which are also easier to guess. After all, your network-account password has to compete in your memory with all the other passwords/PINs that we are asked to remember nowadays.

There are more secure methods available than username/PIN. If a system administrator wishes to know more about them email: info@nephronline.org

These are a number of software programs to help you stop your children from visiting nudity/sex/gun/bomb/alcohol and other unsuitable sites on the Web.
These can be downloaded from the Internet or bought through computer retailers. Essentially, they bar access to either sites you have specified or ones which the programs read as being likely to contain inappropriate material. The following is not an exhaustive list.

www.cyberpatrol.com (for Cyber Patrol)
www.cybersitter.com (Cyber Sitter)
http://securitysoft.com (for Cyber Sentinel)

Concern about the activities of paedophiles on the Internet has prompted a number of organisations to offer Websites with advice to help stop children putting themselves at risk. Again, this is by no means an exhaustive list.

www.parentsonline.gov.uk
www.quick.org.uk
www.iwf.org.uk (Internet Watch Foundation)
www.chatdanger.com (ChatDanger, a relative newcomer from ChildNet International)
www.childnet-int.org
www.childline.org.uk

You have to bear in mind, too, that the Internet is a relatively anonymous medium. Users can -- and do -- pose under false names, identities and even "change sex". Paedophiles often pose as children themselves. And remember that no software program is infallible.

Your best protection relies on trust between you and your children and an updating of the "Never Take Sweets from Strangers" message we all remember for our childhoods.

The standard way to navigate on the Internet is to use the Back and Forward buttons on the top task bar of the browser. But there are quicker ways to return to sites or pages you have visited during a session on the Net.

In Netscape

Try www.bigfoot.com

It's not comprehensive because people's email addresses often change.