|Whatever we do the hackers will be ahead of us so there is no complete solution.|
However, I regard TinyWall as a good start because you can simply block everything online except that which is essential for your particular use. It is small, simple and effectively an interface to your Windows firewall with outgoing blocking. You obviously have to be aware that if anything that goes online fails to work then turn off Tiny Wall to see if that helps and therefore needs to be adjusted. It has a learning mode for that purpose. See here:
It works on Windows 8 too (I'm using it). There is a learning curve but it is fine for experienced users.
Always pop back and let us know the outcome - thanks