This question is very similar to the question asked in https://meta.stackoverflow.com/q/349802/ except the bold text
If there exists a question in that has an answer but not an accepted answer and the date of it was for so long ago that there is great chance new/better answers might come along. Users don't pay attention to old questions that are already answered without asking it again to be more recently.
As a general rule, your first option should be to start a bounty on the question with the express purpose of attracting more attention to it.
It may be the case that the question does not have an accepted answer because a) the original poster did not judge any of them to provide a sufficient answer, or b) the original poster has stopped participating on Emacs.SE. In either event, if you start a bounty, you will have control over who gets the reward for the hard work. You just won't be able to accept the answer on behalf of the OP.
