Question: Do yeast die after bottling? 

My second batch of beer have been stored in bottles over a month now without producing any co2.
I want to add some priming sugar to start the fermentation again, but I'm unsure if it will help.

Answer: 
I have just revived a liquid yeast that was in the fridge for 2.5 years, I cleaned it up, did a starter and its like new.. I took some microscope samples and didn't see any bacteria infection or mutations and even made a little fun video on it, for anyone interested...

[co2 gas bubble moving under the slide, live sample from active fermentation](https://www.youtube.com/watch?v=UQQQuAF74Ig)
The question has essentially been answered, but I'd like to suggest that you also check out the following rather informative write-up regarding the yeast lifecycle which I've found informative:

<http://www.beer-brewing.com/beer-brewing/brewers_yeast/yeast_life_cycle.htm>