In the intro section, in the same place every time (before entering the Witchers' Laboratory), the screen freezes showing the staircase and a sword. The weird thing is that the cut scene dialogue continues and afterwards I can still control my character because the map in the upper right-hand corner is still functional. Using that map, I succeeded in learning the spell, worked my way down the hallway, and cleared the debris hoping that the new loading screen would catch everything up. But alas, the frozen view of the stairway remained.

Can anyone help?

This bug might be persistent in your save game. As you're at the very beginning, I'd start anew and don't save over autosaves.