A question on another site asks, I have a laptop ... Now I am trying to install Windows 7 and it shows a message saying "Driver not found".
Whereupon a commenter asks, What is the "it" that shows the message?
I would think that was an existential it, which cannot be attributed to anything in particular. In any case, if I had structured the question myself, I would probably have intended so.
Q: Is this a case of an existential it?
This question is not about the subject of the example. The question relates to English language, grammar and esp., the concept of the existential it. Please see also the tags for an idea.