Some of you, notably, those who are using Microsoft Internet Explorer, may have noticed peculiar behavior from your system and browser. You may be getting popups at random, with or without a browser window open. Software may be mysteriously getting installed, your bookmarks may change, and attempting to use search engines may cause your system to cough up "enhanced" (yeah, RIGHT) results.
Is this normal? No.
What you're experiencing is an infection of adware or spyware. Some cruel advertisers would like nothing more than to sneak it onto your system so they can turn your desktop into a barrage of ad space they can sell at a premium as ad space before a captive audience. ("Captive audiences" are supposedly the greatest thing ever in advertising. Just ask, say, the Transit Television Network. Go ahead, ask them about it.) In addition to displaying advertisements, spyware captures your personal information; names, addresses, e-mail addresses, passwords, and even bank account information may all be captured.
So... how do you get rid of it?
Automated removal tools exist for many common spyware apps. Spybot-S&D (Search & Destroy!) and Lavasoft Ad-Aware are capable of removing all kinds of nasties. For the particularly annoying CoolWebSearch parasites, look here for more information and tools for its removal.
Unfortunately, spyware is often installed using security vulnerabilities in the Windows operating system and Microsoft Internet Explorer. But how can you keep it from coming back, or getting on in the first place?
The first step, of course, is to keep up to date on Windows updates and security fixes. The second step is to block spyware from getting installed through your browser. Spybot S&D has the ability to run in realtime and block spyware from being installed or making changes to your system settings. Ad-Aware has an Ad-Watch feature in registered versions that probably does the same thing, but I've never tried it.
The best thing you can do to avoid spyware is to not use Microsoft Internet Explorer, and to do a bit of research on any software product before installing it. Alternate browsers you can use include Mozilla and its ultra-fast compact little brother, Firefox. (Note that once in a while when using Mozilla, you may see an advertising network trying to push an .xpi installer file for a "Free Access Plugin" - REFUSE IT.)
Before downloading or installing software, it's a good idea to do a quick search to see if it is, or contains, spyware. A quick Google search for "(name of application) spyware" will usually be quite helpful here. If you unexpectedly get a popup advertising some piece of software, or asking you permission to install it, while surfing the Web - it IS spyware. Trust me, it is.
Finally, to those of you out there using Linux or Mac OS systems - I don't know of any spyware *yet* that targets your system. This is NOT to say that it will not exist - as soon as advertisers figure out a way to shove it onto your system and sell ad space, they'll do it. Be careful out there...