Playback suddenly won't work anymore, loud buzzing sound

Ive just downloaded audacity today so I’m very new to this. I am trying to record my guitar using a Vox amplug amp going straight into my laptop. It has been working OK up until just now, when all of a sudden nothing I record will play back, not even the click track will play. All I get is a buzz sound and the bar doesn’t move along, it seems stuck at the beginning. The waves are there but no sound. I have tried restarting my computer but still no luck.
What could have happened?

We can’t see your computer. Please give the version of Audacity and version of Windows (see the pink panel at the top of the page) and the make and model number of the computer.

What device are you trying to play to? Is it still connected? Please open Help > Audio Device Info top right of Audacity. Right-click in that window > Select All then right-click > Copy and paste the information here.

Have you been changing settings in Preferences? Recording Preferences should show Audio to Buffer of 100 ms (that setting affects playback too). Project Rate bottom left is most compatible at 44100 Hz.