Welcome,
Have you tried other Characters?
Press the enter key by itself to hear if Hal responds.
Make sure you have the proper checkboxes selected in the General, Brain, and Character sections.
Sometimes selecting another voice like the L&H one, do a Test the Voice, then go back to the one you normally use.
Restart Hal after doing these items.
You should be able to select many Plugins like Age & Gender, Loneliness, MarkovL5, and more.
Try some other characters and if you're still having issues let us know. Good luck!!