I would like to know how to replace my basement (hopper type) windows, that are set in the concrete foundation.

More than likely you will need to remove the window sash unit. Then with crow bars pry the metal frame out of the opening.

If the sash is hard to remove you can cut the hinge areas with a sawsall or hacksaw. These windows are usually installed before the floor is framed. They're installed in a channel in the concrete.

With the windows removed install 3/4" pressure treated wood around the window opening. These can be secured with concrete fastners. This way you can install a vinyl basement window and the window can be secured to the 3/4" wood.

Just remember when ordering the window to subtract for the wood thickness you will being installing in the opening.

As I said in my answer to someone else, I replaced mine with glass block, I get all the sunlight but none of the leaks. It was a great Idea in a finished basement.