I recently had a question that needed answering. I did come across a similar question, but it did not have any answers. I ended up posting my own question. Is there a way to re-post an unanswered question? By linking the previous question to this re-post, the original poster may also get their question answered (assuming the re-post is answered, possibly because its a new/"hot" question that caught the attention of an active member with an answer).
Lots of ways to boost an unanswered question. Adding a bounty is a great way. If your question is different enough, a new question is warranted.
One possible way to benefit the the person asking the original question, and helping to get good answers to it, is to edit it.
By editing the original question, if the edit is approved, you make the question more detailed, clearer, or in some manner better than it was. In its improved condition it may interest others enough to invest the time in creating answers. You don't get your question flagged as a duplicate, and you help improve the site for others - both with a better question, possible answers, and less "noise" when someone else uses the search function later.
I believe the original poster will be notified of the edit, and will be notified of any new answers, or comments to the question. So you won't have to "link" to anything. And, as an edited question,it will be bumped to the top of the home page as well, where it will have a new chance to attract answers.