You seem to have misread part of my post. I asked if you had any static on the internal speakers if you plug or unplug the headset plug. The reason is that there is a device that shuts off the internal speakers if something is plugged in. Plugging and unplugging the headset might work something loose or give some indication the internal speakers are at least putting out some type of click or static when this is accomplished.
If they do not make a noise, it doesn't really prove anything, but if they do it might help in troubleshooting.
I am assuming you have not disabled the speakers, or turned them down since the sound stopped while you were playing something. Do you like to play the sound really loud??
As far as external...