Running Windows applications on a computer connected to the Internet without antivirus software is insanity to say the least. There are countless viruses and worms that can be introduced via the Internet to any computer. Your wisest investment for your computer is your antivirus software. It should also be your highest priority to purchase.

For the benefit of the new computer user, let's explain what a virus scanner is. Authors of viruses and worms insert code into programs that will do damage to a target computer if run. This code can come in the form of a file with a .exe extension on the filename or as a Microsoft Word or Excel macro. These are the most popular delivery methods. What happens usually is that you will receive an email attachment or your web browser will run a script and it will invoke the damaging code. Damages are invoked depending on the virus. Some will deny you further access to the Internet. Some will even install there own email sender and spread the virus to everyone in your Outlook address book by sending unsolicited mails with the virus attached. The reason you need an antivirus program is so that it can catch the introduction of this software into your computer and either delete it or isolate it in some way. Folks work to discover the attributes of a new virus and then write ways into the antivirus software to detect the virus or worm. This is called detecting the "signature" of the virus or worm.

Many new computers come with an antivirus package already pre-installed. These pre-installed antivirus packages come with a 90-day evaluation license for automatic updates of virus definitions. When the 90-day period expires, you are given the choice to renew the license for usually a year or if you do not want their product then you can buy another one. If you continue to use the antivirus program you will probably not receive updates of new signatures and therefore will not have protection from new viruses. This is where you would be wise to shop a little more to find the antivirus scanning program that meets your needs.

Freeware antivirus software is virtually nonexistent. Usually if you do find a freeware antivirus program it does not have three very important features. The first feature is the ability for it to scan for viruses introduced into memory or while Windows is running. This is an automatic scanning feature that requires no human interaction. The second feature is the ability for virus and worm signature updates to be automatically applied via the Internet. You also have to manually download the signature updates and apply them. The third feature has to do with support. You do not get the vendor support for freeware antivirus programs like you do with the ones you pay for. You might find information on Internet forums but the live technical support from the vendor is just not there.

Microsoft has an excellent program where you can get 90-day trials of antivirus programs. These are fully functional trials and you can see how they will work with your system. The link to this offer is at:

http://www.microsoft.com/athome/security/viruses/wsc/en-us/default.mspx

Try them out and pick the one that suits you the best. Make sure you check out the Downloads32.com Discounts tab (http://www.downloads32.com/discounts.htm) because you will probably find an antivirus package that qualifies for a vendor discount making it even more fitting to your budget. Some antivirus programs may not work well on your system because they are resource-intensive. Keep in mind that the automatic scanning has to do this task at periodic intervals and this will consume resources such as memory and processor time. So by comparing all the trial antivirus programs you can be certain of the one that will work the best for you before you spend money on licensing it for your use.