I often want to ask a question, but there is another question that is exactly the same, but none of the answers for the other question actually solve my problem. I don't want to post a new question, because it would be an exact duplicate, so what should I do in this situation?
This can be a tough situation, sometimes. But there are some options.
First, as yoda noted, is putting a bounty on the question. This is the preferred method, and takes at least 50 reputation you can spend. That also bumps the question, so it doubly gets extra attention.
What follows are less-desirable options...
You could edit the question, or propose an edit if you do not have enough reputation. But your edit should be of high quality, and should not change the meaning of the question. If the edit needs approval, this won't be a quick way to bump it.
You could post a new question, anyway. But be specific about yours. Probably link to one of the former and state clearly why you are posting anyway. And 'I don't like the former answers' is not a good reason. (There were no good answers could be...) You still risk being down voted and closed as duplicate, but if you are honestly sure that there are no good answers to the dupes, you have tried a bounty and editing, this might be your last resort.
finally, Never do this: Post an answer on the question that asks for answers.