The most basic fundamental of securing your Windows-based computer is doing patch management.
So what is patch management?
Patch Management is your Windows Updates. With billions of people around the world using the Windows operating system there are always bugs found and usability issues. Patch management is how Microsoft and various software vendors keep Windows and these various applications up-to-date.
The reason they are the basic fundamental of security is because often these bugs exploit flaws that hackers and mischievous could use to get into your computer.
Microsoft issues these patches constantly as required, but primarily they get issued Tuesday and as such most computers try to install these updates on Tuesday nights.