A virus that infects your computer is not all that unlike a virus that infects your body: it slows you down and can be passed from you to the people who you keep in touch with. But the good news is that preventing viruses is not difficult.

Just as you can prevent infections in your body by taking simple steps like washing your hands, you can prevent viruses from infecting your computer. An up to date anti-virus program is key for keeping malicious files – viruses – off of your computer's hard drive.

Viruses most commonly infect your computer through email, through world wide web servers and even through the network that your computer is connected to. Viruses may be an executable file sent as an email attachment or incorporated as a macro function in a document written in Microsoft Word or Excel.

Once a computer is infected with one or more viruses, it is not difficult for those viruses to spread. If you forward a Word or Excel document containing a macro virus to a network server, the virus will replicate on the computer of another user who opens it. If you email the document to another user as an attachment, when they open the file their computer can become infected. Similarly, if you add the file to a website and it is downloaded, if the user has not installed software for preventing viruses his or her computer is likely to become infected as well.

Therefore, preventing viruses is an ongoing process – one that is important to undertake.

While it may seem like a big task, preventing viruses is not difficult to do. The first simple step is to make sure that your computer's software is current. Security updates will be posted for your operating system to patch areas that may be targeted by viruses. Set your computer to automatically check for operating system updates.

Similarly, because a number of viruses are spread within individual programs rather than through the operating system, it is important to check for program updates – particularly those for Microsoft Word and Excel.

Speaking of software, another important step for preventing viruses is to install anti-virus software on your computer. There are a number of popular anti-virus brands as well as effective but less common programs. Take the time to determine which anti-virus software is best for protecting your computer based on your computing needs.

And, of course, once you have installed software for preventing viruses, make sure that you keep that software up to date. Check to make sure that it is operating from a current list of viruses and that it is set to protect your computer from viruses at all times.

That way, you will be able to scan documents that you receive in email before opening them. You will also be able to scan the documents that you have downloaded from a web site, because even those files stored on trusted sites may be infected with one or more viruses.

By scanning documents ahead of time, you will be preventing viruses from infecting your computer. However, if you have not scanned a document and are unfamiliar with its source, be sure to disable the macros contained in the document.

In addition to scanning documents and disabling macros, you can take other steps to prevent viruses. You can avoid sharing files except when absolutely necessary. You can delete emails – particularly those with attachments – that come from sources that you do not recognize.

And, of course, one of the best means of preventing viruses from infecting your computer is to be aware. Know what viruses are out there, how viruses are written and spread and how they will affect your computer so that you can detect them early and stop those that get through from spreading.