I'm wondering if I have messed up some setting on my computer.?

Yahoo keeps screwing up sh*t. They changed this a few weeks ago. You'll note that there are two categories, "Discover" and "Answer".

While the latter should list the answers the way you're used to, "Discover" will use some other way of determining their order (like listing those on top that haven't gotten an answer yet, for instance).

Since I mostly answer questions in a single area, I "fixed" the problem by using a bookmark.

I don't know that there's a way to set a default listing type.

Doh! Of course! Use answer. Sometimes we try to add something to make things look new and we distract from the k.i.s.s. principle and the elegance of simple options.