For some reason, I can't yield ANYONE. I've seathed my weapon but even my quest NPC keeps slaughtering me, making the game unplayable.

My only guess is to run away until I'm out of trouble, then fast travel to another town here I can only hope to be arrested....

Their aggression may just be too high for them to give a damn. There's a lot of factors and variables that contribute to a successful yield.

Yesterday I accidently got about 10 guards chasing me and none of them would yield. I had to run across the town and find a guard who didn't know about my bounty, then I pickpocketed him so I could get arrested and pay off my bounty.