It is the dawn of a new year and a new decade. I bet you made a long list of new year resolutions - lose weight, quit smoking, buy a house, and so on. I really hope you have some tech resolutions on that list, too. Resolve to set your PC right, protect it from virus and make it run as efficiently as possible.
Let's start with your OS - operating system. Regardless of which version of Microsoft Windows you are using, make sure it is up to date. Windows is very powerful, but it is not infallible. Patches and updates, released on a periodic basis, fixes security holes and bugs that could compromise your machine.
Prevent hacks and crashes (or at least try to) by running Windows Update at the start of the year.