Here's a couple more tips that may help.
One pound of dried beans equals 2 1/2 cups.
One pound of dried beans will yield 5 1/2 to 6 1/2 cups of cooked beans, depending on size.
Spread the beans out on a towel, sort out and discard any debris or shriveled beans.
Salting the beans during cooking makes them tough.
To check the beans for doneness, place a few beans in a spoon, blow on them and if the skins burst and split they are done.
Don't just let the pot just set on the stove or in the oven, you've got to add water as necessary to keep the beans moist, but don't get impatient and add to much water, and drown the beans.
good luck---sp