Beginner - No Sound Playing?

[Engulfed]

Consider me a complete beginner.

I installed Pro Tools First, opened up the default "Blues", click play and no sound comes out (and my volume is definitely up).

I click Playback Engine, and see it set to Realtek High Definition Audio. I try changing to my regular output device from my LG TV. I then get the message that the project must be restarted. I restart. I open up. No sound and playback engine has returned to Realtek.

I tried reinstalling and making sure to set default output device to LG TV, but it still says Realtek when I try again, and of course, no sound.

What do I do?

Edit: I have found a couple of Google-Searched threads with somewhat similar titles. Yet they all state these complicated audio terms and combination of numbers that are totally confusing, so I still have no idea what to do. Again, consider me beginner.