The best anti-spyware and anti-malware
Using an internet-connected PC without anti-spyware and anti-malware protection is rather like walking through the bad bit of town covered in bling, waving big wads of notes around and shouting "I am very bad at fighting!" Luckily you don't need to have big wads of notes to ensure that you don't get ripped off through your router or mugged via modem: as we'll discover in our feature, there are plenty of seriously good PC protection apps that you can get for absolutely nothing.
As with any free software, pay close attention to the installers: some apps really want you to install bundled software, and they often do so by making installer screens really misleading in the hope that you'll just merrily click okay to everything. Given that the whole point of these apps is to remove unwanted software from your system, trying to stuff unwanted apps into your PC is a bit off. For more information, see our guide to avoiding potentially unwanted programs (PUPs).
Have we missed an anti-spyware program that's saved your system? Let us know in the comments below.
1. BitDefender Antivirus Free Edition
Discreet protection from malware, spyware and online security threats
BitDefender is the strong, silent type. This anti-spyware and anti-malware tool doesn't even ask questions when you install it. What it does instead is use a range of tactics to identify bad things. It has B-Have, which looks for apps behaving badly; link scanning to identify cons; proactive malware and spyware scanning that can detect threats nobody has encountered before; and boot scanning every time you start your PC.
Ad-free, nag-free and hassle-free, it's a great product that runs quickly and silently while you get on with something more interesting.
Its comprehensive suite of tools to protect your PC makes BitDefender our top pick. Read on to discover nine more of the best free anti-spyware and anti-malware programs.
2. Panda Free Antivirus 2016
Cloud-based security that takes the pressure off your PC
We're big fans of Panda's security products, and Panda Free Antivirus is smarter than ever before. It's cloud-based, with all the heavy lifting happening on Panda's servers - so the load on your PC is lessened considerably.
As ever there are paid anti-spyware and anti-malware products that offer more features - Wi-Fi scanning, password management, encryption, parental controls and so on - but Panda offers excellent real-time protection and is ridiculously simple to use.
If your PC is a little underpowered, Panda could be the anti-spyware and anti-malware tool for you.
3. AVG Anti-Virus Free 2016
A simple interface and effective scanning with remote activation
If you prefer software that keeps quiet, be warned - AVG Anti-Virus Free 2016 is quite vocal with its notifications, and irks us from time to time with pop-ups telling us we've done something fantastic with regard to our online safety.
As an anti-spyware and anti-malware app, though, it's very good. The dashboard is user-friendly, there's protection not just from downloadable threats, but from dodgy links too, and you can use your mobile to scan your PC remotely, which is pretty clever.
The paid-for Pro model has more security options - it has more robust download protection, offers data encryption includes a firewall - but the free version offers decent protection for most PC users.
4. Ad-Aware Free Anti-Virus+
All the anti-malware and anti-spyware essentials, but lacks phishing protection
Like many security software firms, Lavasoft offers its Ad-Aware Free Anti-Virus+ software in a free version in the hope you'll upgrade to its paid-for products - so it doesn't have some of the more advanced features you'd pay money for, such as phishing protection, parental controls and a digital file shredder.
What it does have, however, more than covers the essentials: it scans downloads, checks for spyware, offers safe browsing via a list of known malicious websites and has a game mode so security notifications don't interrupt your frag-fests. Not bad for no money.
5. MalwareBytes Anti-Malware
An excellent tool, but the free edition lacks real-time protection
You can use MalwareBytes Anti-Malware free for as long as you like, but there's an important caveat: real-time protection, the fast 'hyper scan' mode and malicious website blocking features all expire after 14 days - and that means you're missing out on some of the program's best features.
MalwareBytes has a deserved reputation for destroying malware and spyware that other programs miss, and its chameleon technology - which once again expires after a fortnight in the free version - means it's less susceptible to attacks that deliberately target security software.
Think of the free version as a short-term savior or a test drive; the Premium version costs £19.95 (about US$30, AU$40) per year.
6. SpyBot Search and Destroy
An anti-malware and anti-spyware stalwart that's ideal for diagnosing infections
SpyBot Search and Destroy is a veteran of the malware wars, dating back to the first adware in 2000, and while it doesn't scan for viruses - that's in the Home version, which is $13.99 (about £10, AU$20) - the free version does a decent job of finding and fixing adware, malware and spyware.
It's more of a system repair tool than a system protection tool, however, and you need to be careful where you get it from: there are fake versions in circulation designed to cause damage, not fix it. The version linked here is the real deal.
7. Avast Free Antivirus
A comprehensive package with built-in password management
Avast is another old-timer, and has been protecting Windows from malware and spyware since PCs were made of wood. Avast Free Antivirus is the lightest, fastest version the company has ever shipped (the bad old days of security software slowing your PC to a crawl are thankfully long gone) and it supplements the anti-malware protection with a nifty password manager and home network monitoring, which can identify weak points in your Wi-Fi.
As with most free products, not all the goodies are available for nothing, so for example if you want anti-phishing protection or spam filtering you'll need the paid-for version, but the free edition is still a very comprehensive security package.
8. Emsisoft Emergency Kit
A lifesaver if your PC is already infected, but not a preventative tool
Most security software tries to stop malware and spyware getting onto your system. Emsisoft Emergency Kit doesn't: it's the 911 call of security software, the app you use when your PC's been poked by something unpleasant.
It's designed to be portable, an app you carry around with you on a USB stick, and its system requirements are tiny: just 200MB of RAM, so it'll run happily on any PC with 1GB memory or more. With two million malware signatures, Emisoft Emergency Kit can restore almost any infected PC to rude health.
For experts only - get detailed reports on a misbehaving PC
Originally developed by Trend Micro and now available via SourceForge, HijackThis isn't an app for the faint of heart or tech-phobic: it generates an exceptionally detailed report on your system, enabling you to spot potential problems and malicious software.
It's very fast and very thorough, but it's about malware and spyware methods rather than specific products. It tells you what's going on and it's your job to interpret it and take action. In the wrong hands, that power could be disastrous. This is one for experienced users only.
10. SUPERAntiSpyware Free Edition
An outdated interface belies a solid manual malware scanner
Not just anti-spyware - SUPER anti-spyware. Does it live up to the name? Yes and no. SUPERAntiSpyware Free Edition lacks real-time protection and scheduled scanning, so it's a tool you need to remember to run manually, and the interface appears to have been designed in the dark by maniacs.
The core product is a solid one though, with lots of scanning options for picking up malware and spyware, registry repair, behavioral scanning and daily threat updates.
Perhaps not super, but pretty good.