Asus 51J headphones unplugged problem

Update: I just go it working properly. I forgot I used a headphone extension when I first plugged it in mid-gamet. When I used the extension again on the cord and replugged it in I got a balloon saying "audio device was just plugged in" and now it is working properly again! Before I was just unplugging and replugging the headphones in without the extension and it wasn't working. But it's okay now. I wonder what caused that?

Hello, the problem I am having is that my laptops speakers are always on, even with headphones plugged in.

Here is how it started, and it's happened twice in the past...
I normally connect my laptop to an HDTV and have playback devices set to "Realtek HDMI Output" and have headphones plugged into the television to listen.
But today I plugged my laptop into my desktop monitor and started up a video game, and I forgot to switch playback devices to "Speakers" and forgot to plug my headphones into the laptops headphone jack.

So while in mid-game I plugged in my headphones and changed playback devices to "speakers" but the RealTek HD Audio Manager ballon pop-up said "just unplugged a device from the audio jack". The opposite of what I had done. Now the laptops speakers are always on even with headphones plugged in, and I no longer get a pop-up window when plugging or unplugging headphones in the laptop's headphones jack.

The problem has happened before, and it happened the exact same way. I switched playback devices and plugged in headphones mid-game because I had forgot to when switching the laptop from my TV to my monitor. And when I did that the balloon instead said I unplugged the device from the audio jack.

I solved it before by doing something like plugging the headphones in and restarting the laptop, then starting the game and midgame unplugging them or something like that.
Only I can't remember what steps I did to solve it before.

Can anyone help me? I have no idea what exactly causes this and how to fix it.