Forgive me, but I'm not understanding what can and can't be done with an expired ATP written.

I took the ATP written in 2007, but I have yet to be employed at a 121 operator.

If I were hired tomorrow by a 121 operation, would my expired test be available for use, or must I retake it since it has expired and I've not been employed by a 121?

Also, if an airline says I must have the ATP written completed to be eligible for employment, would my expired one count or would I need to take it again.