I just read the elder scroll to learn the dragonrend shout, and Alduin appeared to fight, as it should happen. This time however Alduin is taking no damage, whether on the ground or in the air. I have tried bows, axes, maces, battle axes, hammers, spells, shouts. Nothing works, I have never had this happen before and no matter what I do nothing fixes it. I tried reloading, running away and entering the cell again, running away and waiting. This glitch also happened right after I downloaded 1.7.

Do you have a save from before you use the scroll?

If so, load it, travel to a distant city like say markarth. Wait there 48 hours or so and return and read the scroll.