Viruses, Worms and Trojans are malicious programs that can cause damage to information stored in your computer. Those malicious programs can also slow down your computer, your Internet access and might even use your computer to spread themselves to your friends, family, or co-workers. You may infect your computer in many ways, such as opening a spurious e-mail, downloading or copying files from unsafe sources, or simply clicking on a pop-up in a web site.

Spyware is a general term used for software that performs certain behaviors such as pop-up advertising, collecting personal information, or changing the configuration of your computer, generally without appropriately obtaining your consent.

Any computer that is connected to the internet or any external network is at risk of hacking or unauthorized intrusion by people who would steal information stored on your computer or use your computer in ways that you did not intend.

Use and regularly update firewalls, anti-virus, and anti-spyware programs

One of the most effective ways of defending your computer is to use a firewall and up to date anti-virus and anti-spyware products. A firewall works by filtering information coming from and going to your network/computer and/or the Internet. It identifies and rejects information that comes from a location or source known to be dangerous or contains information that seems suspicious. A firewall reduces the possibility of virus attacks and spyware intrusion. Anti-Virus programs can stop Viruses, worms, and Trojan horses. An anti-spyware program helps stop misuse of your computer by spyware.

Note that many software vendors bundle firewall, anti-virus and anti-spyware in a single offering, while some offer only one or two components. Make sure that you do protect yourself against all three threats, even it means buying software from separate vendors.

Additionally you need to make sure that you do run the software at regularly scheduled intervals and keep the products up to date. New security threats are being discovered practically every day, and a protection that you installed a year ago will no longer be safe. Make sure that you renew the licenses as and when they expire.

Install updates to operating systems and other software programs

Whenever security updates or service packs become available for your operating system, browsers or other third party programs, it is very important to promptly download them and patch your operating systems and programs. These patches are created to protect systems against potential attacks. Make sure you update any software you use for browsing the Internet (Internet Explorer, Firefox, Netscape, Safari, etc.) and other software programs that communicate or interact with the Internet, like e-mail, Web servers, and remote desktop software are especially susceptible to attacks and should be kept current on patches and version levels.

Passwords

Passwords and other authentication methods are ways that systems verify that you are who you claim to be. If someone authenticates as you, they can access your computer, as well as other systems that you access under your identity and cause undesirable consequences. Don't share your passwords and access codes, don't store them in unencrypted files, and don't write them down unless you then place them in a locked, secured location. Default passwords, names and dictionary words, even in different languages, can be easily guessed or cracked so use complex ("strong") passwords that are at least eight characters long and have numbers, letters, and special characters in them.

Lock your workstation/laptop

One of the fastest ways to compromise a system is to simply walk up to an unattended, unlocked workstation or server and access the system. Be safe and lock your system when you leave it and configure your system to automatically lock after a short period of inactivity. While this precaution may seem superfluous with your home computer where you are unlikely to have random visitors, reports of home computers being compromised during large home gatherings are not uncommon.

Backup regularly

There are many ways you can lose information on a computer - a destructive virus, a power surge, lightning, floods, a big magnet, or sometimes equipment just fails. If you regularly make backup copies of your files and keep them in a separate place, you can get some, or even all, of your information back in the event something happens to the originals on your computer.

Exercise caution in using the Internet

The Internet has many wonderful facilities, but it also provides innumerable opportunities for misuse. No security software or process is foolproof, and installing safety mechanisms is no substitute for proper care and use of the Internet. The proper use of the Internet, E-mail, instant messaging, etc, is a large topic in itself.