Today's spyware isn't just annoying--it's a real and growing security threat. If you're like most PC users, you're wondering how to stop it. And stop it you better. Fail to take action, and you'll be battling increasingly powerful and plentiful spyware at work and home.

So what can you do? Anti-spyware software is great, but that's only part of the solution. Here are 8 other things you need to be doing right now if you're going to head spyware off at the pass.

1. Know your enemy

Prevention starts with knowing the enemy. So what is spyware? Exactly what it sounds like--software that spies. Download a program that has spyware bundled with it and you are unknowingly giving others access to everything from your credit card numbers and passwords, to visited websites and downloading habits, to documents and data stored on your harddrive. Scary, isn't it?

Other related culprits include:

Adware (a.k.a. "pop-ups"): an application that pops up advertisement windows and banners randomly or based on current browser content.

Hijackers (a.k.a. "jackers" or "switchers"): applications that change your browser home page, default search engine and even redirect you from sites you try to reach.

Cookies (a.k.a. "tracking cookies"): small files that track data such as website preferences and passwords for repeat visits, which spyware gathers and spreads without your knowledge.

Adware is mostly annoying; it's spyware and hijackers that do the most real damage.

2. Say Good-bye to Internet Explorer

Thanks to the security gaps inherent in their design, Microsoft Windows and Internet Explorer (IE) basically open the doors to spyware. Switch to alternatives Firefox or Opera, which both block pop-ups by default, and encourage friends and family to do the same. Firefox is free, while Opera costs a few dollars. Both give you a significant jump in spyware protection.

If you depend on Microsoft's Outlook e-mail client, you may have no alternative but to use it and IE. At the very least, you can slow spyware's infiltration through the browser. First, disable Microsoft ActiveX support. Next, open Internet Explorer and click on Tools > Internet Options > Security > Custom Level, then check the boxes that force ActiveX controls to ask permission before running.

Finally, install the Google Toolbar , which blocks pop-ups. It works on Internet Explorer 5.5 and higher (you should always be running the latest versions of browsers anyway to take advantage of security improvements).

3. Be Careful About What You Install

Spyware purveyors do a wonderful job convincing people to download spyware daily. One of the most commonsense ways to avoid spyware sneaking it's way onto your computer is to pay attention to what you're installing. Before you download any new program, especially freeware, stop and ask yourself if you know and trust the source of the program. (Download.com and Tucows.com are examples of reliable sources.)

Most reputable software producers avoid including spyware with their programs, but if they do they generally provide you with the opportunity to opt out of "extras" during the installation process. Take the opportunity and avoid potential problems early.

Which brings me to a simple but effective prevention method: read every new program's license agreement. If there's any mention of transmitting information to a third party, that could mean spyware. It sounds like a pain, I know; so many of us are in the habit of clicking on "Okay" without understanding what we're agreeing to. But understand that spyware publishers don't want you to read the licensing agreement. They count on your bad habit to ensure you install the spyware they've packaged with their freeware. Bet you want to read those licensing agreements now, don't you?

4. Run at least two spyware cleaners.

Vendors will say their tool catches everything but in truth no spyware cleaner can find and eliminate every piece of malicious code. All utilities have blind spots, and you'd better believe that spyware programmers know how to exploit them. So run two utilities and run them regularly. Clean a system and reboot into Safe Mode, then clean it with a second tool and reboot again. We recommend buying one cleaner and installing a second freeware program, our preferred tools are Paretologic's XoftSpySE with SpyBot Search & Destroy.

And, of course, make sure your software is up to date. Even freeware adds new capabilities regularly. In general, you should be checking for and installing updates for your operating system, email client, browser and ISP to take advantage of security enhancements.

Continue on to steps 5-8