Program stopped playback or record

Audacity v 2.1.3
Win 7

I recorded a file yesterday and was editing it this morning and then Audacity stopped playing back or recording all of a sudden.
Is it possible I activated a setting somehow?
I reinstalled it twice, reset options during the installation, but it still does does not play back.

The cursor/timeline just does not move.
Could someone please help me fix this
Here is a quick Jing video to show this behaviour.

Thank you.

If you had accidentally changed a setting in Audacity, then “Reset Preferences” during (re-)installation would put the setting back to the factory default.
I suspect that it’s more likely that a setting has changed in the system’s sound settings. Have a look in the Windows Sound Control Panel.