Antivirus softwares are great. They protect you in real-time from active threats and they can scan your system. I think you all know that. The thing is that I don't recommand them. Why? Because there are false positives, and every antivirus software has one pro and one con. The pro are that most all modern free antivirus softwares have real-time protection, the con is that they slow down your system, like Avast for example. Avast has also too much features. It should be an antivirus, but you have also a system cleanup, a password manager, etc.
Kaspersky, for example, is a russian company. And we all know that Russia isn't the best spot to make your company, especially a security one. Avira, literally the unremovable "antivirus", comes with an entire "security suite", slow down so much your system like Avast. It's like their umbrella is transparent and that the rain (malware) goes through it XD. But thankfully, there is an alternative, which is...
Yes, Malwarebytes is the alternative and doesn't have all of these problems. The premium version has a real-time protection while the free one doesn't, but it's just enough since it won't slow down your system. Malwarebytes also doesn't include all the features Avast has for example, it has just the essential features, which are a system scanner and real-time protection (only premium, could be useful). Malwarebytes also detects less false positives and more real threats than other antivirus softwares I've ever tested. It truly is the best anti-malware, and not antivirus, as many other people would say.
You might consider getting these softwares to get rid of PUPs and (potential) malware :
AdwCleaner - Owned by Malwarebytes, this software is mainly designed to remove adware and PUPs, but sometimes even potential malware. It's a great tool and a great alternative to SUPERAntiSpyware, since SAS detects Adware.Tracking cookies (but the software itself is complete trash), and AdwCleaner can detect them (and obviously even more things).
Revo Uninstaller Free - This software lets you safely uninstall any software on your computer without any traces left (or almost). It is a great alternative to Windows' built-in installer