If you have experienced some of the issues caused by either of these types of virus you will already have some knowledge of the devastating effect they can have on your PC.

Although each of these viruses has the capability to render your system inoperable in a similar way, the way in which they enter your system is very different.

Macro viruses

"Macros" can be found inside of all spreadsheet, word processor and slide show presentation software applications. There is nothing harmful about a macro itself. A macro is just an action file which automatically carries out program commands. Unfortunately, virus creators have found ways to infect these files and macro viruses are now the most common type of computer virus around today.

Before the birth of the macro virus, in order to create a virus the author would need to be sufficient in complex programming languages such as assembly language, but since the introduction of the macro virus it is now possible to write a simple macro virus using simple macro language commands.

Trojan horse viruses

A Trojan horse virus is a type of program that appears at first glance to be a legitimate and useful program but is in fact harmful to your system. Often found within downloads, this form of virus is usually installed by the user and can cause a variety of security and privacy issues.

As in the case of Macro viruses, Trojan horse viruses must also be executed by running the file in which they are contained. Simply downloading an infected file onto your system will not trigger the Trojan horse to activate.

It is important to remember that no matter what internet security measures you have in place, it is still possible that a virus may find its way onto your system. To fully protect all of your data, it is important to create backups regularly. Many antivirus software programs now include a backup feature which allows you to store copies of your photographs, music and important document files on an online server, allowing you to recover all of your data should the worst happen. If you're antivirus software does not have this feature included, there are numerous backup services available online for a small fee.