Beer not carbonating

I made a barleywine over three months ago. It is close to 12%. I left it to carbonate for about two months after adding 3/4 cup corn sugar. The beer is still flat. I even tried adding some sugar directly to a couple bottles and let them go for about a month, still nothing. Could it be that I need to add some yeast back to work on the sugar? Could the yeast of died after sitting in that high of alcohol? I have never had this happen before.

Thanks for any help
Scott

Welcome!
Often times Barley wine will need a yeast back.
Since it's bottled...you could add back a granule or 2 or 3 of dry yeast to each bottle. It will not take much more than that in my experience. I would try and use a strain that is nearly the same as whatever your original yeast was to avoid getting a higher attenuating yeast that would cause excess carbonation.

I had a feeling that was the problem. This is my third barleywine; the first two I had no problems but the alcohol % was lower. I am amazed at all of the threads. Thanks again, Scott