This question already has an answer here:
What can we do to help new users who come to the site with a problem but find a question already exists, but it doesn't have any answers that solve the problem.
This SU "answer" (deleted, so only available to diamonds and 10K SU users) is a good example.
The way the site is set up at the moment the following things may happen.
- They get comments, some polite, others less so telling them not to post questions as answers.
- They get down-votes (which don't actually affect their reputation score, but it's not nice.
- They delete their "question-as-answer".
Now they have another problem. Do they just wait (having bookmarked the question perhaps) in the hope that it gets answered soon or do they post their own question?
If they do the latter then the following will happen:
- Comments about not asking duplicate questions will get posted.
- They will get downvotes.
- Their question will get closed and eventually deleted.
Not very welcoming at all.
Now all the above will get the problem some attention - either the original question is bumped or at least re-read by those voting to close, so someone new might see it and post an answer, but is this really the way we want to treat newcomers?
So repeating myself from my previous answer:
... do we need a "I'm having the same problem" button on a question and if it's clicked enough times within a certain period the question gets bumped? There would have to be limits on the number of times a user can click it and perhaps it should only be available to registered users to reduce people bumping their own questions
For reference this is the original SO answer I linked to - as you can see it's been edited to include the information from the comments and so is now a useful answer. Perhaps this is one way we can encourage people - explain that an answer needs to include new information.