Standard operating procedure is to delete questions where the answer is unlikely to be helpful to anyone else ever in the future of the Internet.
For example, if someone made a stupid mistake (like a typo in their code), then it's unlikely anyone else who lands here from Google will find that question or the answers to it very helpful. Questions like that should be deleted. If the asker doesn't delete them him/herself, then someone should flag them for moderator attention. Use the "other" option and explain why the question should be deleted in the free-form textbox.
However, for questions where the answers are good and useful, the question should probably be left alone, even if it is sub-par. The goal here is to build up a reference where answers to common programming problems can be found, not just to help one person solve their problem. No matter how silly or stupid, if one person had a problem, it's fairly reasonable to assume that someone else might have that same problem later.
Most of the time these questions will be closed by the community, probably as either "too localized" or "not a real question". Voting to close only requires 3,000 or more reputation, and the agreement of 5 different users. Once a question has been closed, users with at least 20,000 reputation can vote to delete it. It only takes 3 delete votes.
Yes, let me show an exemple on SO : the OP asks why a DeleteFile() call could fail, and it appears that the code is ok, only the file name (extension) was wrong, hence the function call fails. The OP comments "Solved it", the questions stays in the "unanswered" filter: DeleteFile() function always returns error code 2
I was about to suggest that that question should be answered, explaining that error code 2 is defined by the Windows headers as
ERROR_FILE_NOT_FOUND and demonstrating where/how to find the documentation that contains the error code information.
But…I see the asker has already accessed the documentation and made that discovery. So there seems to be little to add in the form of an answer. It literally goes without saying that the extension is part of the file name, and if you've got the incorrect file name, Windows will be unable to find and delete the file.
I say delete the question: