As long as I know there are no computer that is invulnerable to viruses, even a Mac. Because computer viruses can self-duplicate – like a Worm – and spread from computer to computer, interfering with data and software. It just like biological viruses that infect people, spreading from person to person, and computer viruses infects personal computers (PCs. Some viruses are mere annoyances, but others can make serious damage to your data.

Computer Viruses can delete or change your files as well, steal your important information, load and run unwanted applications, send documents via e-mail, destroy all OS (Operating System). So, whether your computer is a Mac or a PC even a Linux you still need to protect your computer against viruses.

Two types of computer that usually attack a PC

• Trojan Horse

Trojan Horse is a destructive program that usually disguise as a game, a utility or an application. When Trojan Horse runs, it does something devious while appearing to something useful.

• Worm

This type of virus can propagate itself from across computer. A Worm can duplicate itself and make could make your computer to crash.

The following are some basic tips to protect your computer from those viruses.

• Install Antivirus, Before you install any application you usually use for your work such as Adobe Photoshop or Microsoft Office or any other little application, I suggest you to install Anti Virus Program. Such Kaspersky AntiVirus has proven to be good defense for my PC against virus. There are other type of AntiVirus in the market you can purchase such AVG, BIT Defender , Norton, Norman and Avira. It's worth your computer safety
  
• Update Database Daily, Computer software is developed to more advanced and beautiful technology almost daily - so - as well as the virus. You need to update your Antivirus database daily (if you can) to make sure that your computer is in high protection to current virus. You don’t need to purchase Antivirus new version every year. Just update its database regularly and your computer – might – safe. Usually the Antivirus Software provide two methods for this updating, first by connecting to internet the software will automatically update the database, the second you can download the database from the official website and install it into your computer.

• Scanning Computer Regularly, Schedule the software to scan your computer daily or weekly, including your computer sharing network. This is to make sure your computer has no suspicious data that potentially can damage your OS. Because, sometimes viruses can sneak into your computer without you being noticed.
• Scan Portable Storage, Today, we have portable storage such as FlashDisk and MMC (Multi Media Card) that we are able to share datas like musics, pictures and videos easily. But, before you share data from computer to computer using these device, it’s highly suggested that you scan it first, just to make sure a virus isn’t in it. You don’t want to have a breach in your computer just like I did, do you?.

Suspicious Data ?

Usually, even if a virus found its way onto a computer, the virus could not actually infect the machine, unless you're by some means fooled into executing the virus by opening it and running it just as you would run a legitimate program.

So, if you have found a suspicious data on your computer and not sure what is it, you have to delete permanently by pressing Shift + Del (if you run Windows OS)