not sure how this format is going to work but ill just go with it for now, trying to share free software that helps in day to day computer tasks, while computer techs usually have heard of these (or similar software) others spend money on premium equivalents. please let me know if you find any of my information to be outdated and I will do my best to make corrections as needed. Im going to try to stay very high level and not get to technical as each software can easily justify its own page if i delve in to deep and most of you will just get bored.
Its far to easy to find free-bees here for any outside of business (who expect a different level of support) to be paying. You can combine Anti-virus with anti malware, but do not load more then one antivirus.
My go to for anti malware is Malwarebytes, there are both free and premium version, free one will work for most but you have to initiate the scans yourself, it works well enough that it is also my favorite weapon for removing infections from pcs after the fact.
I used to go AVG free for anti-virus but recently it has been quite bloated, i have been surprised with Windows Defender (built in to windows 8 and 10) or Microsoft Security Essentials for windows. follow this link for side by side comparisons of the more popular options
Third important type is the root-kit removal, a root kit infects the boot sector and sometimes the bios of a computer, they are usually the gateway for other infections, every remove a virus to reboot and see it re-installed? again there are some options that can be found with a simple search I will include the link to my favorite (Mcaffe) but really if you have this type of infection it may be time to call a computer tech for a deep analysis. If your computer savvy but lack experience http://www.bleepingcomputer.com/ is a good source for info