I suppose you have already figured it out since you have answered the older message but to answer your question there are a few ways to find previous questions.
1. Search bar at the top of G2G and put in a keyword (obviously some keywords are not very effective - the old Smith and Jones problem)
2. If the question is about a specific existing profile it can sometimes be easier to find the profile which should have a link to the question (assuming the box provided for who the questions is about was filled in by the asker)
3. If the question was tagged with a surname, place, project, etc. you can look at all recent questions with the tag. For example: http://www.wikitree.com/g2g/tag/Nutt
4. If it is a question you have recently answered or commented on you can look at your g2g profile and see all answers or recent activity - you can also do the same thing if you can recall the name of any other person who was involved in the discussion (not just the asker)
5. You can use a search engine like Google or Bing and use advanced searches. For example adding site:http://www.wikitree.com/g2g/ after the keywords will only display results from Wikitree's G2G. Google has an 'advanced search' page so you don't need to memorize or look up the operators and keywords. As far as I know Bing does not have a similar advanced search page but it does have it's own advanced search terms (operators and keywords) which are not identical (for example the keyword prefer:)
Of course, if it is a question you are going to look into and plan on answering you might also mark it as a favorite.
The last option of course is to ask a new question and hope the question you are looking for shows up as a related question - but that is probably the most inefficient way to find an older question.
