I have some good and bad news for you.
Bad is that you can't find them using those URLs anymore. They don't exist.
Good is that those threads still are there but in the
Archives. You will have to enter a word or two (use AND/OR) between words and select ANY DATE from the drop down box. The search feature is pretty quick compared to the old one and will highlight in a magenta color the actual words you are looking for in the thread when you open one. Very helpful.
If it is something that was discussed in the past few months it might be found in the Search on this page (look at top of page). After a certain time we archive the threads to make things faster here and make the searches more compact.