The below pictures reveal extensive damage under the siding. On the right is the begining of the restoration process. After treating the existing wood with the Multiprime and allowing to dry, I trowled in a mixture of Layup and Laminating Epoxy and sawdust. I held this in place during cure with sheetrock dams covered by plastic and screwed into the wood.

On the left I have created sheetrock dams to hold back the epoxy sawdust mixture. The picture on right is the after cure view.

Since those photos were taken I've discovered a quicker way to make the "epoxy dams". I cut little pieces of wood about the size of paint stir sticks. They're about an inch wide... made to match the brick molding steps. The last 30 windows involved a lot of rotten corners where the bottom two inches of the brick molding side trim was rotted. Anyway it was quick to stuff the holes with my epoxy/sawdust mixture and then use a Staple Gun to attach the plastic-wrapped strips of wood.... instead of using the sheetrock screws shown in the photos.