When I click Terminal in Launchpad, it says "The application Terminal is not open anymore." But it shows up in the Force Quit window and it has the open-app indicator on the dock.
I can't quit the app, restart or shut the computer down.
I think this could be the root of the problem:
I was running a program in Terminal overnight and then it said something like, "Terminal is paused...run out of memory." I quit it and when I opened it again, this happened.
Using MacBook Air OS X El Capitan v. 10.11.2