Each word below can be changed into a new one by re-arranging the letters and then preceding them with the same two letters, in the same order. Can you determine the two beginning letters and the five new words?

STAIN
VIRAL
GRAIN
ANGER
STINGER

HINT:
The first of the two beginning letters for each new word is A.

Answer:

The two beginning letters are AR:

ARTISAN
ARRIVAL
ARRAIGN
ARRANGE
ARRESTING

Credit: Idea - Will Shortz
NPR Weekend Edition Sunday Puzzle
January 25, 2015