Is Windows a Virus? 

 No, Windows is not a virus. Here's what viruses do:

 1) They replicate quickly - well okay, Windows does  that.

 2) Viruses use up valuable system resources, slowing  down the system as they do so - okay, Windows does  that.

 3) Viruses will, from time to time, trash your hard  disk - okay,  Windows does that too.

 4) Viruses are usually carried, unknown to the user,  along with valuable programs and systems.  Sigh... Windows does that, too.

 5) Viruses will occasionally make the user suspect their system is too slow (see item 2) and the user  will buy new hardware. Yup, that's with Windows, too.

 Until now it seems Windows is a virus but there are fundamental differences: Viruses are well supported by  their authors, will run on almost all systems, their  program code is fast, compact and efficient and they tend to become more sophisticated as they mature.

 So Windows is not a virus.

It's a bug.