Malware is a combination of the words malicious and software and refers to a type of cybercrime.  This is a type of software whose sole purpose is to cause harm to a computer system.  Types of malware include viruses, worms and bots.  If your computer is affected by malware, it may have been infiltrated by a bot (short for robot) and used without the your knowledge:  your computer is now a zombie.  Frequently, the botmaster will use the bot to connect your zombie to other zombies, which creates a botnet.

These are all very clever and interesting terms, but in reality, they pose a real problem.  Malware has become one of the most pressing security problems on the Internet. Cyber criminals use these tools to send spam mails, to launch denial-of-service attacks, and in the worst cases, to steal personal data such as mail account or bank credentials.

There are ways to protect your computer from becoming a zombie.  If you use a Microsoft operating system, be sure and install the updates you receive.  They typically contain security patches that combat the latest "hole" found by the masters.  You should also invest in anti-virus and firewall programs and keep them up-to-date.  

How complex are your passwords?  Malware can very easily crack simple passwords; so make sure you avoid dictionary words (not just English), make sure it's at least 8 characters long, and toss in a few numbers and capital letters.

Finally, exercise discretion when browsing the Internet.  Be choosy about the sites you browse and if you don't trust a link in an email, don't click on it.