Best way is to save the message number (or put a link to it in your browsers Bookmarks/Favorites). There is also your message list in "My Computing.Net".
Otherwise search the post list for your name - Search/Find feature in your browser can help if you know the page. You could also search for the title or part of it. Make sure you know which forum you put it on (Windows 7, Vista, XP, Security etc).
Was it this one?
If so, it was posted right here on the "Windows 95/98" forum. It should have been put on the "Mac" forum (if that is what you are using).
Ms Hulot's boat