If your computer does not have an anti virus program yet, install one RIGHT AWAY.

Even if you have one installed, make sure it's an up-to-date version. Similar to the antispyware programs we discussed previously, antivirus programs come in different sizes and flavors. Most are retail versions while a handful are free.

The market rate for a barebone antivirus program is about US$39. Some vendors provide an entire suite which provides antivirus protection, firewall, antispam, antispyware, etc. The average price is about US$79. All of these vendors provide a free 30-day trial for you to evaluate the program before purchasing. Take note though that most of these vendors will require annual license renewal. So the US$39 or US$79 you plop down does not mean you don't have to open up your wallet to them again the following year.

When selecting an antivirus program especially the basic barebone type, make sure it has an integrated email scanner. This will ensure that when you download your emails, they will all be scanned for malicious attachments. A good antivirus program should automatically integrate its scanner into whatever type of email program you use. If you use any of the popular web-based email services, they usually offer free antivirus scans of your attachment before download.

A few antivirus vendors offer a free online scanning service. How it works is that the vendor's server will send a few files for you to install on your computer which will aid in the scanning process, partly by sending data to their central server. The data sent will help them determine if your computer is infected. While most of them declare that no personal data is retrieved, the decision ultimately rests on the user if they feel comfortable with using such a service.

Part of good computer security habits is keeping your important programs up-to-date. These include your antivirus, antispyware, firewall, and other related security programs. Most of these programs have an option to automatically check their headquarters for updates and it's a good idea to keep this option checked.

It's not enough that the main anti virus or anti spyware program is updated. You have to make sure that your virus definition files or DAT files are up-to-date as well.

Whatever your antivirus program, a common feature they all share is the DAT file. The virus definition files store the information about recently discovered threats. If you do a virus scan of your computer today, but your DAT files are from a month ago, then the virus scanner will not be able to identify the new viruses that have been discovered since that time and if your computer has been infected say two days ago, the new infection will go undetected. Each antivirus program has a built-in automatic updater for the dat file. You'll just have to read the program's manual to determine how this is done.