Why is a computer used by children particularly vulnerable?
Most children learn to use computers from a very early age. That means that even quite young children have the technical skills to send and read emails, find web pages, play games, music or videos, and even install new programs on a computer. The trouble is, although 8-year old children may be quite capable of doing all these things, they cannot be expected to have the maturity to understand the consequences. That is to say, they can't possibly know if the email they have received, the webpage they're looking at, or the game they want to play are produced by decent, responsible people or by criminals intent on defrauding you of money, or worse.
What are the possible risks to the computer my children use?
Children are especially vulnerable to the scams used to install hidden malicious software on your computer. They could easily be tempted to install a game or play a piece of music, which turns out to be a Trojan (dangerous program in disguise) that could be used to take control of your computer or steal personal information from you. We have encountered many cases of family computers that have become riddled with viruses and other malicious programs, because children have been given unrestricted access to them. Remember, criminals don't have moral qualms about using to children to steal your money, or worse, and the easiest way to install a password-stealing program on your computer is to disguise it as a child's game and make it available for free.
How do I keep the computer my children use safe?
To prevent your children from inadvertently installing malicious programs disguised as games etc, there are two courses of action that will greatly reduce the chances of this happening. Firstly, make sure that you have done a thorough security check on the computer your child uses, and don't economise on security software. The best antivirus programs catch almost all malicious programs, whilst the worst ones miss up to a third of them. There is advice on which program to get for maximum protection in the "Antivirus Programs" section of this site. Secondly, set up a separate, non-administrator account on your computer for your children to use, and to put a password on the existing account(s). What this means in practice is, when your children log on to the computer (i.e. click their name on the Welcome Screen), they will be able to use all the programs on the computer to send email, surf the web or make pictures etc, but they will not be able to install any new programs or change the computer's security settings. So, if they try to install a new game which actually contains a virus, the system will prevent them from doing so, and the computer will remain safe. This doesn't mean your children can never install new games on the computer, but they will have to ask you to do it for them. Don't install anything unless you're certain it's from a reputable company (if in doubt, ask a computer expert). Of course, there will come a time when you consider your children are sufficiently aware and responsible that you can take away any restrictions on the computer they use. Just make them read this website before you do!
How to set up a non-administrator account for your children
If you have Windows XP: Click Start, Control Panel, User Accounts, Create a new account; type in your child's name (or something like "kids" if more than one child is going to use the account); click Next, then, under Account Type, click the Limited button, then Create Account.
If you have Windows Vista: Click Start, Control Panel, User Accounts, Manage another account, Create a new account; type your child's name (or something like "kids" if more than one child is going to use the account), then ensure that the Standard User button is selected, then click Create Account.
NB: you MUST put a password on your own account and any other administrator accounts, otherwise the whole exercise is a waste of time. If a malicious program tries to install itself while the child is using the PC with his or her non-administrator account, Windows will pop up a prompt asking for an administrator password; if there is no password, the child only has to click "OK", and the program will be allowed to install.
To add a password to an administrator account, go to User Accounts in Control Panel again, click on the name of the account you want to add a password to, click Create Password; type in the password twice, and a hint to remind you what it is if you forget. Make sure that your children cannot guess the password, even if they can see the hint.
NB: for advice on protecting your children themselves, please see "Protect your child"