He's good at what he knows, but he gets completely flummoxed when new problems arise.
I'm still flummoxed as to what to do!
If you still find yourself completely flummoxed, pay someone else to do the work for you.
We were recently shown an issue of the New Yorker magazine and we were totally flummoxed thereby.
Once you see the dizzying array of totes available at some sites, like Like.com, you may be flummoxed on how to choose just one!