Even today, I personally have no idea what the US went to do in Afghanistan. Iraq, at least, had oil. But, Afghanistan? What was the point?
(And in case you genuinely don't know: the Taliban were openly harboring Al Qaeda including Bin Laden. The US ordered them to either hand him over or allow the US to pursue him. They refused. So, the US eliminated the Taliban.)
Removed the Taliban from power, they still very much exist.
As the other poster said, Afghanistan's connection to 9/11 was clear, not even Afghanistan denied it.
But I'm curious why you say "yet another country." Between September eleventh and October seventh which other countries do you think the US attacked?