If you find your problem solved, mark the concerning thread accordingly by editing the initial post (which is meant to be chronological the very first in a thread) and choosing the green check-mark from the icon list.
Why, if I may ask? Let me explain a little bit more: as I understand it, the idea behind the "green checkmark" is that a "solved" thread will only be used as reference for future related questions; however, the thread remains open, causing confusion, as someone else can post a new question (related to the original one) in that thread, which makes the "solved mark" totally useless and meaningfulness.
If the idea behind this "solved mark" is to announce that the current question has been answered, then the thread should be closed, and I don't think that's the point of a forum (that would make sense in some other answer-question sites).
So, I suggest two options: 1) If a thread has been marked as solved, then the Administrators should close it. (I wouldn't support this option) 2) Eliminate the requirement to green-mark a question as solved.