So I'm up fighting the last dragon boss, but he's glitched for me.... -.-

All he does is rotate in a spot in the sky summoning fire balls and sometimes breathing fire, when I use the shout, he just glows blue. He doesn't land or anything. When his health does get to 0 (after about 140 iron arrow shots) He just continues on casting fire storms and breathing fire.... sigh, I though I was past the major bugs when I couldn't even get past the intro to the game.... Help? I've tried reloading, killing him with the shout, and without. He won't land, he wont move...