Windows defender to a large extent has been a life saver and I believe its sufficient enough to keep your system safe except its a targeted attack. Also, you might want to install another one if you feel that would give you peace of mind but be careful on the exact one you patronising so you don't bring in issue for yourself in a willingly manner.

Aside from the suggestions on the right way to keep funds safe, I think another way is to do right especially on the part of government. File your returns if needed, pay your tax as at when due and government would be the least of your headaches.