I don't think it's as black and white as Manning is terrible in the cold. Yes, it's true, he certainly struggled with velocity last night and that was in contrast to arguably the best cold weather QB of all-time. However, the Broncos still have plenty of hope.
1. Julius Thomas was a major loss, as tight ends have ripped that Pats defense this year. The Patriots match up extremely well with Denver if J. Thomas is out, since Talib might be the league's best matchup versus D. Thomas while their #2 corner (Dennard/Ryan) is also very adequate to contain Decker. Jacob Tamme roasted the Pats last night, so just imagine what J. Thomas might have done.
2. Manning is also playing with a high ankle sprain, and last night's game was REALLY cold, not just cold. I'm not sure that they'll need to deal with such extreme wind chill again.
3. Biggest point is that the Patriots allowed 400 plus yards to the Broncos because they completely sold out to the pass all game, figuring it's better to allow 6 yard runs than 40 yard passes. Manning did not play as badly as people on here are making it out to be. He took what the defense gave him for the most part, and the Broncos had some success moving the football. Had Manning really been as awful as pundits are claiming, why not just stack 8 in the box to stop the run? I think we know the answer to that.
4. Not trying to defend Manning- again he didn't play well and often struggles in the cold- but I hardly think Denver is cooked. If I were a Broncos fan, I would be much more concerned about that defense. I think they are pretenders on that side of the ball.