"My computer is kinda slow. I think I have a virus." That is by far the most frequent declaration I hear from clients. When I ask why they think so, they'll use any oddity in their computer's performance to support their diagnosis. Their suspicion may be triggered by a jumpy mouse, an unfamiliar icon or even a screen color they describe as "not quite right." Usually my clients are wrong -fortunately, but occasionally I find that a virus or other malicious code has found its way onto their computers.
In the old days, a virus was a virus. Their authors made infection obvious. Old fashioned viruses could be cruel by deleting your files or just a nuisance by typing extra characters into your MS Word documents. Many even splashed a nasty "ha ha" message on your screen, making it clear that your computer was infected and who was claiming credit for doing it.
Today, malicious programs have evolved and morphed into so many forms that a new category called "malware" has been created to encompass all the variations. Some are so subtle that users can go months without realizing their computers are infected.
Here are some terms that will help you more accurately describe a malware problem on your computer.
Virus: Damaging programming code that inserts itself into and becomes part of another program. It can spread from computer to computer by way of a network, disk, file-sharing or infected email attachments.
Worm: Similar to viruses in that they replicate functional copies of themselves, but worms can also be standalone programs that reside only in the computer's memory. Worms exploit weakness in the computer's operating system or browser or they can use pop up messages to trick users into launching them.
Trojan: Named after the wooden horse the Greeks used to infiltrate Troy, a Trojan is harmful software that looks legitimate, thereby tricking users into launching it. Trojans are frequently designed to create an entrance to your computer for hackers to access information such passwords and files.
Spyware: Programming that that is on your computer for the purpose of secretly gathering information and relaying it to advertisers. Some popular "free" programs are bundled with spyware which is often installed without the user knowing it.
Browser hijacker: Programs that alter your browser so you'll be redirected to web sites you had no intention of visiting. Some more virulent hijackers add bookmarks for pornographic web sites.
Many of today's better antivirus software include detection for all forms of malware. If you suspect that your computer may be infected, you can get a free online scan with a product called Housecall at www.trendmicro.com
So if your mouse keeps jumping all over the screen, your computer might have a virus. Or your new semi-transparent mouse pad might just be freaking out your optical mouse.