As far as passwords are concerned - unless, like me, you're a programmer who can afford to spend the time to build his/her own personal secure password vault software - I highly recommend using LastPass. I've been using it myself quite a bit in the past and can say it's probably your safest bet; and it's also really cheap too! Besides, I wouldn't really go as far as getting anxious about browser history and all that stuff. 

Now moving on to the security of the files on your computer..  I've been using Avast Premier for over 4 years and can guarantee you that no form of hack (of course, unless you're being specifically targeted by some genius hacker) will ever be able to breach your security. Avast offers standard antivirus, ransomware file protection, secure DNS, secure browser for banking, active online protection stopping you from entering phishing websites or downloading malware, etc.

Just my 2 cents, but that's  how I recommend someone stays safe.