We're working on an internal project that involves (among other things) sending notifications programmatically to Jabber users. It's at that stage where it works for some people and not for others. There are two versions of code doing the sending (different OSes). There are two OSes on the clients, and there are about 10 different clients.
So it's time to break it down. It's overwhelming to try to tackle it all at once, but if we make a table we can see what works and what doesn't, and start to try to get all "Y"s into the table, and see if there are any patterns. It gives us a base to work from.
When you're lost, write down what you know, manipulate the data to visualize it, and you'll see a way out.