request more information as a comment to the question
Yes, if you want to help.
ignore the question
If you don't want to help. No one's making you do anything. I ignore everything between 1 am - 7 am and also while working on stuff.
flag the question
If you are < 3k rep it may make sense to flag to vote to close as not a real question, on the condition that it's not a real question.
give an answer in a non-forum way knowing that could be totally wrong but worth a try
Probably not. If you have a pretty good guess what the problem is and want to try posting as an answer then sure. Be ready to edit or delete if you are far off base, and if this happens even once I would be more conservative going forward.