The IOC is an international non-governmental non-profit organisation and the creator of the Olympic Movement. The IOC exists to serve as an umbrella organisation of the Olympic Movement. It owns all rights to the Olympic symbols, flag, motto, anthem and Olympic Games.
It's members are to be found HERE
Actually, I couldn't find any reason, why a country with a NOC could be excluded from the games - this didn't happen ever before, since there are no such rules.
And I only just noticed that this is posted in 'Politics'