There are very few computer users whose lives were not touched at one time or another by malware in the form of viruses, Trojans, adware, spyware and/or worms. These are all pieces of bad and unwanted software developed by seriously dysfunctional people from countries whose names are hard to pronounce and whose parents think they are sweet.
Malware is defined as software that makes your computer work bad and the earlier versions of Windows were the first malware known to man.
Spyware is software that can monitor your browsing habits and even take full or partial control of your computer. It’s like an intelligence agency or a rude boss.
A Trojan is a piece of software that claims to do one thing and ends up doing some other illicit thing, much like the government or teenagers. Trojans have been known to locate password information and send it to people who know what to do with it. Trojans do not replicate like viruses and are considered dysfunctional loners.
A virus is software that copies itself onto a legitimate program and spreads from one computer to another. Viruses can cause data to be lost or corrupted and can be a blessing to workers who need a break from their desktops.
Adware is software which runs in the background of your computer and makes popup ads, well, pop up, causing the user to scream and call the nearest nerd-friend who will not only ask how could you be so stupid over and over but who will also refuse to drive to your home at 2:00 am to try to get the pop ups to disappear despite your crying.
Worms are like viruses and consider themselves to be the baddest in the land since they stand alone and do not need to attach themselves to another program. They are the non-aligned movement of the malicious software world.
Currently there is an MP3 circulating via the popular peer-to-peer file sharing system Limewire which, when run, makes gullible users download PLAY_MP3.exe. Once the naive user runs the exe file pop ups begin to appear, and life becomes questionable again.
I have been using Avast antivirus, which is free for non-commercial home use and comes in Windows, Mac and Linux versions. However, if you want to make your computer safer from the full range of evils of the Internet world I recommend making one of the many commercial Internet security suite companies wealthy. The best suites are from McAfee, Symantec, and Trend Micro. I do not have a preference and your choice might depend on which you prefer to give your credit card information to.