You may know not right away. As I said, everyone's systems is different and sometimes you have to experiment to see what works best. Some programs are more resource heavy than others and may slow down your system in such a manner that you are not willing to live with. The rest is a matter of personal preference (past experience) or recommendations/opinions by others.
The combo should consist of a trustworthy anti-virus and anti-malware solution as I noted in those two topic discussions (and here
) along with Windows built-in Firewall. You can also add other anti-malware solutions as stand-alone scanners....see Supplementing your Anti-Virus Program with Anti-Malware Tools
Keep in mind that an offer of free anti-virus or anti-malware software is essentially a marketing technique
...a way of advertising and enticement to get folks to try a product and if they like it, to purchase the full (Premium/Pro) version which typically provides more features. Marketing and promotional strategies are built into the vendor's business model as part of their operating costs. Bottom line...it's all about generating revenue and finding new and creative ways to do so
. As such, users may have to deal with occasional nagging pop-ups or nuisance advertising and prompts to upgrade to the paid version.By using such free programs, you are essentially agreeing to the terms of the vendor's service which includes those annoying pop-ups and ads.
In some cases you may be able to disable them through the program's settings if the vendor included an option to disable them. If the vendor does not have such an option listed, then your only alternative is to switch to another product if the pop-up and ads annoy you that much.
In regards to anti-malware products, the primary benefit of paid software is that most of them offer additional features such as real-time protection
against malware infection and free technical support. In contrast, free versions are limited...typically used as stand-alone scanners or to provide some behind the scene protection so there really no need to allow them to run at startup and consume system resources.
Whether one chooses to use a free or paid for product really depends on their personal needs, financial situation and what level of security they are attempting to achieve.
Also keep in mind that many anti-virus vendors are bundling toolbars and other software with their products as a cost recoup measure. In fact, all free Anti-virus programs now come with toolbars or other bundled software (and annoying prompts to upgrade) except Bitdefender Free, Sophos Home, Microsoft Security Essentials and Windows 8/10 Defender