The best security is intelligence. Be a smart user, be skeptical, assume that all clickables can be dangerous.
Microsoft Security Essentials is not capable of todays real-world protection requirements. As you will see in the graphs below, it ranks the lowest of all product options.
At minimum use Ad-blocking extensions for your browser. ublock origin
. AdBlock or ABP are no longer considered secure. ublock (non origin) should also not be used as it is essentially a stolen project.
Paid products and free products are both equally capable of providing adequate protection. I highly suggest that you do not buy "Premium" versions of software. Just avoid the free products that tend to annoy you in some way.
. VPNs, without one you can assume that any and all network traffic is being logged and monitored. https://zenmate.com/free-vpn/
Now to the most recent relevant results.
File Detection (Scanning)
As you can see MSE is TERRIBLE. Not even comparable to any single tested product. Most products besides Trend Micro do well here.
Real Time Threats
Again, MSE is abysmal but so are many other solutions here. I would personally not be happy with anything below 99%.
This is more of an annoyance, but the uninitiated user may end up quarantining files they will need.
All solutions seem to effect they system in similar ways. While some minmaxers might care, I consider these results almost insignificant.
System Cleaning: CCleaner.
Also great for uninstalling, removing programs from startup, actually cleaning the registry properly, and can legitimately "wipe" free space from your hard drive(overwrites deleted files). I suggest doing a system clean before scanning to reduce the scan-time.
Secondary Scanner: MalwareBytes Free
(Not the Free trial of the Premium -DO NOT ACCEPT THE TRIAL)
Last Resort: ComboFix