How Do I Remove Viruses, Adware, Malware, etc.?

Background.
How Do I Remove Viruses, Adware, Malware, etc.? The short and snippy answer (for the moment) is 'get a Mac.' ;-)

But assuming you use Windows in one flavor or another as most of us do, read on. All of the software I recommend below is free for home and non-commercial use.

Symptoms? If your PC has recently become much slower than usual, displays unrelated pop-ups, or takes the browser to sites you didn't choose, you may very well be infected.

Avoid Malware
It's of course best to avoid malware (I'll use this term to refer to malware, viruses, adware, etc.) to begin with. To that end I recommend six things.
1. A hardware NAT router, even if you only use 1 computer w/ your broadband connection.
2. Enable the built-in Windows firewall.
3. Run some anti-virus software.
4. Stay up to date with the OS security updates.
5. Be smart.
6. Use a safe browser.

For a router, pretty much any name brand router will do. I've had very good luck with Linksys but other prefer various brands. The Linksys WRT54G is a very common, reliable, and affordable model. [often under $70]

There are several free and payware software firewalls available for Windows. I used to use the free ZoneAlarm for 3+ years but stopped about 2 years ago. It was slowing down my machine and between the built-in Windows firewall and the hardware router I wasn't convinced it was really necessary. It is true that the 3rd-party software firewall will tell you if you have malware 'phoning home,' but if you follow these other instructions that shouldn't really be an issue. Also, when most people are asked by the software whether or not to allow some outbound connection they usually have no idea what they are being asked and just click 'Okay' anyway, defeating the purpose.

I think all versions of Windows since and including XP SP2 have the firewall enabled by default.

There are many choices for anti-virus software. I recommend staying away from the large suites like Norton & McAfee. They are often bloatware and will slow your machine down quite a bit. I use and recommend the free AVG and Avast AV tools. They both update regularly and work well. I've been using them for several years and never had a problem. Note: Only use one or the other on a given PC, not both. [I've heard good things about Clam A/V but never used it myself.]

Make sure you have the automatic updates enabled for Windows.

By 'be smart' I mean be careful what apps you run and what things you click on. Be VERY hesitant to open attachment that come in your email, even from supposedly trusted sources. They could be infected and not realize that they are sending malware. If you go to a web page and a pop-up tells you to click and download something because you're infected, don't. If something tells you it needs to download a new codec for Windows Media Player, don't. There are some exceptions to these rules, but you're better off erring on the side of caution.

Use a safe browser. IE 7 & 8 are much better than previous versions w/ respect to security, but still prefer Firefox and more recently Google's Chrome. If you run Firefox you may also want to run the NoScript extension. It by default disables JavaScript on all web pages/sites, allowing you to selectively enable them for sites you trust. This can be a headache if you're not comfortable with the process.

Assuming all of the above you should be very unlikely to end up w/ malware on your Windows machine. But what if in spite of that you get some anyway, or already have some? ...

Removing Malware
If you think you may be infected there are several free tools you can and should run. I've yet to see one tool that will remove them all, but a combo of 2 or 3 will usually do the trick.

I prefer to run both Spybot and AdAware, one after the other. You may want to run them once a month even if you don't suspect a problem anyway. I've also heard many good things about a new tool called Malwarebytes; I haven't tried it yet but intend to.

So there you have it. Be smart, use a hardware router, and take advantage of the free software. ;-)

Thi is certainly not the absolute final word on the subject, but if you do these things I think you'll avoid the vast majority of malware problems on Windows. And if your machine seem infected with numerous things that the tools simply can not remove properly, the best thing to do is format the drive and reinstall Windows from scratch. Sometimes that's the only sure way to know the system is clean.

Oh, one more thing, if you download stuff from questionable torrent sites and tools like Limewire, you're almost begging to get malware on your machine. Stay away from both.