There are different types of software that can attack your computer and they work in quite different ways. This makes detecting, preventing and removing them more difficult. There are three main groups of malware: Trojan horses, worms and viruses.
A Trojan horse program will not reproduce itself but it does place your PC at risk and vulnerable to intrusions of other kinds. A Trojan horse can allow software to be able to read the files on your computer. This type of attack is a serious threat to your security and privacy. Trojan horse programs are usually installed when you download software from unreliable sources.
Worms are programs that can replicate themselves. They use networks to transmit copies to other computers. All this is done automatically without any user intervention required. Computers that have security holes are vulnerable to worm attacks. This is why it is important to always have the latest software updates from Microsoft.
Viruses are programs that can be copied to infect other computers. Viruses can transfer from PC to PC and can even be code that is executable. Viruses can travel over networks infecting files and file systems.
Whether you choose to have a computer expert help you protect your system or network or you do it yourself you want to ensure that you maintain your computer to protect both it and your privacy. All you need is the right tools and a little knowledge you can be sure that your system is protected.