Advanced system care is not exactly your best option.
Boosted1g, you say that, which is not wrong, since only recently Microsoft has started actively working on Windows Defender as a security suite. Also, Kaspersky has a free version now which is nice. Anyways, you will need 3 layers of security. Anti-virus, Anti-malware, and in browser solution.
Currently, Windows natively has its own anti-virus Windows Defender, and it works relatively well. The majority of the popular providers have free versions of their software to test out, and they also do the job. As for anti-virus, I recommend Comodo, Avast, Avira, Bitdefender, Kaspersky or Norton. All of them proven formidable.
With anti-virus, you usually will need to run anti-malware software. Not every single anti-virus has the full package included. Any of the popular software solutions will be solid as well. My recommendations towards ADWCleaner, Malwarebytes, Hitman Pro, I used them all, they did the job.
For in browser solution, you could use an Adblocker to protect you from malicious ads, uBlock takes this one for me.
But when it comes to the internet, no software will protect you 100%. My tip would be to be aware of what you are browsing and downloading. Do not click suspicious links, avoid shady files. Additionally, be careful with emails, a lot of malware is spread through fake/malicious emails. That is the best way of being safe out there. Good luck!