It’s important here to be clear about the difference between anti-virus software and anti-spyware software: anti-spyware software (like Spyware Search and Destroy, Ad-Aware SE and Microsoft Defender) are only looking for items that are privacy threats, like cookies, keyloggers and other such items running in the background on your system. Anti-virus programs (AVG, Norton, McAfee), on the other hand, are also looking for items that modify your system at the root level, reproduce themselves and try to connect to other computers. It’s a key distinction, because while you can run multiple anti-spyware programs on the same computer, you generally can’t run more than one anti-virus program without some unintended consequences or wacky behaviour on your system.

We definitely recommend using more than one anti-spyware program on your system if you’re serious about your security, as none of the anti-spyware programs we’ve tested are able to catch ALL of the spyware out there. Certainly what counts as spyware is a matter of interpretation in some cases, but it’s always good to have a second opinion and make your own decisions as to what you want running in the background on your system (some cookies for example) and what you don’t.

But don’t forget, no matter now many anti-spyware packages you choose to run, make sure you still run an anti-virus package too, to make sure you’re properly protected from the real nasties. We find that the free version of AVG is one of the best free packages available. If you want to step up to paid software but want your AV software to have a light touch on your system resources, Nod32 is also a good choice.