It doesn't matter how much you want to continue riding beating a dead
horse is not going to get you anywhere.
If
something is already done and over with there is no point in still talking about it.
If something is already
broken there is no point in trying to use it.
Someone breaks up with there girl/boyfriend and continues to bitch about them to there
friends weeks later. That person is beating a dead horse, the relationship is over there is no point in thinking about it since the matter is already resolved with you having broken up.
Relationship = dead horse
Bitching about it = beating it
Trying over and over to start your
car after you've been in an accident where it is clear that the
car is not going to work.
Broken
Car = dead horse
Trying to start it = beating it