The internet is undoubtedly a fantastic resource for families and offers a rich vein of educational content.

However, there are potential dangers - welcome to the seedy world of viruses, spam, trojans, pornography, spyware and other nasties.

These are the Top Twelve Threats No Computer User Should Ignore.

1. Viruses - A computer program that copies itself. They often disrupt your computer system or damage your data. Viruses are usually received by email attachments so be careful opening anything from a dubious source. They can affect anyone, for example, the destructive Mydoom worm affected one out of three small and mid-sized businesses.

2. Spyware - Sends information about you and your computer to somebody else. Spyware may send the addresses of sites you have visited or worse still, transmit personal information. With today's concerns about identify theft this is a real worry. For example, CoolWebSearch may hijack web searches, home page, and other Internet Explorer settings. Spyware is normally received as part of shareware or freeware downloaded from the web.

3. IP Spoofing - A technique to gain unauthorized access to computers, whereby the intruder sends messages to a computer with an address indicating that the message is coming from a trusted host.

4. Trojans - An apparently legitimate computer program that is really intended to disrupt and damage computer activity by sending information, perhaps even passwords onto a third party without you knowing. As an example, recent emails entitled "Osama Bin Laden Captured" attempted to download the "Trj/Small.B." Trojan if the embedded URL was clicked. This trojan attempts to hijack the PC.

5. Spam - Unsolicited mail often promoting products of a dubious financial or sexual nature. Don't leave your email address on websites and internet bulletin boards as they are harvested by spammers.

6. Adware - puts advertisements on your screen. These take many forms including popups, popunders and advertisements that appear later, even if your browser is closed. Some are sent using the Windows Messenger service which allows a spammer to direct an advertisement straight to your computer by sequentially sending messages to IP addresses. Always irritating, they are also often of a pornographic nature.

7. Diallers - for those of us still with dial up modems, dialler programs redirect calls to a very expensive number. You won't know until you get the bill.

8. Hijackers - Hijackers take control of your web browser and may reset your home page, search bar and search pages. They can redirect you to undesirable sites or stop you going to particular sites.

9. Hackers - With so much personal data available online to anyone with a password you must be sure your password is secure. If you are using your mother's maiden name, your cat's name or your birthday then your password is at risk. Here are two tips for making a secure password. Method One - pick two random unrelated three letter words and two digits. Mix them up and what do you have? A secure password such as "red19cat" or "hotpin73". Method Two - pick a short sequence of words such as Now Is The Winter Of Our Discontent Made Glorious' and you have a password of "nitwoodmg". You could even change the I's and O's to digits.

10. Phishing - Emails purporting to come from reliable sources such as Paypal, Ebay or your bank. Often wanting you to verify your account details, they can look very realistic but are generally scams to harvest usernames and passwords. Always open a new browser winder and type the address there, rather than clicking on the link provided.

11. Hoaxes - Chain letters, scams, false alarms. At best they take up time and bandwidth but at worst vulnerable can be victims of fraud. Pass it on!

12. Stranger-danger – For those of us with children - do you know what they actually do when they are online? Are they working on homework tasks, downloading illegal music or pornography? Or are they chatting to strangers in chat rooms? You should consider blocking access to undesirable sites and logging their activity with a surveillance tool. Oh, and don't forget that where children are concerned, computers should always be kept in a family room and never in their bedroom.

Three Step Action Plan

There are three basic, essential steps that should be taken to ensure your PC is kept threat-free.

Firstly, be sensible when opening attachments or following email instructions from apparently reputable sites.

Secondly, make sure you are using the latest service pack of Windows as Microsoft is continually closing loopholes to tighten up security.

Finally, there's a range of low cost tools such as firewalls, antivirus, spam blockers and spyware killers available. Like everything else they vary in quality and you tend to get what you pay for so always do your research first and perhaps try a free trial before getting your credit card out.

About the Author
The author, Kai Chandler, edits http://www.surfcontrols.com which specializes in providing reviews and recommendations of top-rated tools to help protect your online experience.