Malware and Viruses are two different beasts, so you need to protect from both. Antivirus software does not always cover Malware. I run Windoze 8.1 with Norton 360 plus Malwarbytes. Not trying to plug any software, just saying, cover your backsides as well as doing your regular backups (as already mentioned above).
Also, clear your cache in your browsers as well as this is where you leave the best bread crumbs for the hackers and phishing thieves to get their hands on your lifestyle choices.
There are viruses out there for all systems - PC, MAC and Linux too so no one is safe. I have been in the IT game since 1988 and an IT Network Engineer for over 13 and believe me, they teach the programmers how to make these viruses in Uni. So that they will know how to recognize them and how to make antivirus programs.
And yes, you guessed it, there are some that decide to make their own ones to "see what they will do".
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The problem is not the problem...The problem is your attitude to the problem.