The best time to stop a virus is before it starts.  After some viruses get on your computer, they can disable your virus scanner, damage system files and sometimes cause irreparable damage.  However, to prevent viruses you must first know how they get on your computer.

The most common method is through Internet downloads.  E-mail attachments, downloads from web sites, and downloads from file sharing programs should all be scanned prior to use.  Many common files, such as Word, Excel and PowerPoint® documents can contain viruses hidden within.  

Another way viruses access a computer is through an out dated operating system or program.  Many programs including Internet Explorer® and Windows® have many security holes.  As a result Microsoft® creates updates to fix these problems.  Once the updates are released, many programmers and hackers can examine them and write viruses that exploit the security holes.  As a result many viruses are release after the updates are available that make computers immune to them.  For this reason and others, it is very important to update your computer.  To update your computer, go to

One final source of viruses is an unprotected network connection.  There are programs available that scan a large number of computers and find ones that can be accessed remotely.  Once others find that your system is open to attack, they can place viruses on your machine, delete files, and copy private data.  To prevent this use a firewall.