Anti-Spyware Programs:

Basic Free Protection

Scanning for spyware and adware isn't enough to protect your PC. You also need to take preventative steps to ensure that unwanted software doesn't come back. One effective way to prevent spyware and adware from returning is to install an anti-spyware prevention program such as:

SpywareBlaster and SpywareGuard are excellent, free programs from JavaCool. I recommend installing and using both, as they protect your computer in different ways. SpywareBlaster "inoculates" your Internet Explorer browser against the installation of unwanted spyware and adware from the internet. SpywareGuard actively monitors your PC and prevents spyware infestations. Both are easy to install and update.

Advanced HIPS & Rootkit Protection

In the past few years a new generation of anti-malware protection products has emerged. This new type of anti-malware protection, called HIPS (Host Intrusion Protection System), works at the kernel level to intercept malware before it hits your hard drive and infects the system. Although this technology is still maturing, a HIPS defense may be worth looking into for some users. For a run-down of the latest HIPS applications, see this discussion on the Spyware Warrior forums:

Advanced users may also be interested in the broadening array of anti-rootkit programs that are available:

Please keep in mind the HIPS and anti-rootkit applications are both emerging technologies that may not be appropriate for home users who aren't technically savvy.

One of the most prevalent means for spyware and adware to be installed is through Internet Explorer. To prevent spyware and adware from installing without your knowledge and permission, you need to "lock down" Internet Explorer. There are several ways to do this.

Securely configure the Internet zone

First, you can securely configure the Internet zone of Internet Explorer and add sites that you trust to the Trusted sites zone. This means that by default web sites will not be able to use "active content" (i.e., ActiveX controls, Java applets, and scripting) until you explicitly choose to trust those web sites. See this page for instructions on how to securely configure Internet Explorer:

Internet Explorer Privacy & Security Settings

By turns, you could also use this free program, which will automatically configure Internet Explorer for you:

Enough is Enough!

One potential downside to securely configuring the Internet zone is that some web sites will not work properly until you add them to the Trusted sites zone -- a process that some users find cumbersome.

Add bad sites to the Restricted sites zone

Second, you can use another approach to "locking down" Internet Explorer which avoids the hassle of broken web sites by adding known "nasty" sites to the Restricted sites zone. Doing so gives your PC protection against known threats while still allowing most web sites to work by default. To put the clamp down on a long list of undesirable web sites, you can install and use this free program:

IE-SPYAD

If you choose to use the Restricted sites approach of IE-SPYAD, be sure to update your copy of IE-SPYAD regularly, as new web sites are constantly being added to the list.

Internet Explorer is not only the most popular browser on the Net, it is also the browser most widely and easily exploited by spyware pushers to install spyware and adware behind users' backs. Thus, you might decide that Internet Explorer is simply not worth the hassle or risk. In that case, you can install and run an alternative, non-IE browser such as:

All three of these browsers are mature, robust, and fast. Moreover, they have built-in pop-up blocking and several other nice features that Internet Explorer simply lacks. More importantly, all three of these browsers are much less susceptible to unwanted adware and spyware installations. And all three are free.

Note: even if you do switch to an alternative browser, you should still lock down Internet Explorer, as described above. Given that Internet Explorer has effectively been integrated into Windows, it can still be exploited by adware and spyware that gets installed to your system through other means. Thus, locking down Internet Explorer remains important even if you're not regularly using Internet Explorer to browse the internet. 

Windows Update
http://windowsupdate.microsoft.com/

Much of the update process at Windows Update is automated, so it's simple and convenient. The Windows Update site will install a small program to analyze the software on your system and recommend the appropriate fixes. This process takes only a few minutes. 

Once Windows Update has finished analyzing your system, you'll be presented with a menu of downloads that Windows Update deems appropriate for your computer. At a minimum you should let Windows Update install the fixes marked as "Critical Updates." The other available updates ("Recommended Updates," "Drivers and Enhancements") are optional.

Anti-spyware applications alone can't protect you entirely from unwanted spyware and adware. You have to do your part as well by being vigilant in your online behavior.

One of the more common sources for spyware and adware is "freeware" (e.g., Grokster or KaZaA) that bundles unwanted third-party applications. Another common source involves third-party web sites that automatically start the installation of spyware and adware when you visit those sites. These auto-installed spyware and adware programs may initially appear to be plug-ins necessary for the web site itself, though usually they are not.

Wherever you happen to encounter spyware and adware, you will usually be presented with a EULA (End User License Agreement) and/or Privacy Policy. Do not blindly click through these documents. Read them carefully and look for the tell-tale language that discloses the presence of adware or spyware. For tips on what to look for, see these pages:

Other Anti-Spyware Tools

There is a wealth of specialized anti-spyware tools on the Net, many free for the taking. For a more complete list of anti-spyware products, see:

Download and run one (or all) of these free anti-spyware scanners and remove whatever spyware and adware it finds. 

You should also scan and clean your computer with whatever anti-virus program you happen to have installed on your computer. If you don't have an anti-virus program, you can scan your computer with one of these online anti-virus scanners:

... or download and run one of these free standalone virus removal tools:

Visit a spyware removal forum

Once you've cleaned your PC as best you can, visit one of the following spyware removal forums:

Most of the above forums will request that you post a HijackThis! log. HijackThis! (HJT) is a free program that will scan key system settings on your PC and generate a plain text log that you can copy and paste into a post. The volunteers at the above forums will examine that HJT log and recommend a course of action to fix your PC. HijackThis! can be downloaded from HERE. 

Each forum has its own set of instructions and procedures for requesting help and posting a HJT log, so abide by the requirements of the forum you're visiting. Also, do not attempt to use HJT on your own to fix problems. Let one of the expert volunteers examine your HJT log and advise you on what to fix.

In order to help you clean your system, the volunteers at these anti-spyware forums need a good sense for what's going on with your computer. When you're ready to post and request help...

• Start a new discussion topic/thread.
• Give your discussion topic/thread a distinctive title.
• Describe the symptoms and problems you're experiencing.
• Describe what you've already done to solve the problem.
• Copy and paste your HJT log into your post.
• Be patient while waiting for a response.

Note that some of the forums listed above may require you to register for free before posting.

Once your PC has been cleaned, be sure to take steps to prevent it from being overrun with spyware adware again.