While I haven't been very vigilant in enforcing it, pretty much since the beginning Stack Overflow has had a policy against using SOLVED in question titles. There has been a previous discussion of this on our own meta:
Should the headline marked with [Solved]?
I mention this because I noticed one of our more experienced members edited a Community bumped question which had been dormant for five months simply to put SOLVED in the title, although this member was not otherwise involved in the Q&A and did nothing further in the edit.
A few reasons I can see for this, all invalid:
Because you think this is how questions with an acceptable answer should be dealt with -- no, please take the tour to understand better how the site works.
Because you are trying to alert the user that there is an acceptable answer, or, as in this case, that they should probably accept their own existing answer -- no, if this is the case, leave a comment.
Because you think there is a useful, acceptable answer and you want people who see it in a search list to know that -- no, instead:
- Invite the OP to accept the answer with a comment.
- Upvote the answer, which will increase its ranking in search results.
Of course, if you don't think the answer is worth an upvote, then smacking "SOLVED" in the title is a confusing gesture.