Im trying to fix my old save since Dawnguard is on its way and Im just having so many problems. If I walk outside for too long the game freezes, if I fast travel or go threw more than 2 doors the game crashes to a black screen. I tried going into some Dwemer ruins and almost nothing loaded in it, when it finished loading I was in an invisible room were the only things that loaded was a piece of Dwemer armor, a pipe and a door. Also if I try to go to Solitude, to the Bards college, some of the pillars are missing and their is a strange arch in the doorway that takes you inside. I have no idea whats going on, none of my other characters have any of these problems and I even downloaded the unofficial patch 1.05b which fixed a lot of other minor problems but had no effect on these crashes.

Anyone have any ideas what could be causing this? If you need anymore information let me know, but I would very much like to save this character if possible, I spent way too much time playing to do everything over again.

P.S. guards will randomly see anyone, player or NPC, getting too close to them as hostile and warn them off. This is a new bug thats not so bad...yet. Any idea whats causing it?

No ideas, but have you made a clean save for that character? Turn off all mods, load the game and then save?