Complete lack of audio, cannot find a culprit

Recently my speakers have begun simply not broadcasting any audio whatsoever. However, the reason I am here is that I can seemingly find nothing to indicate there is even an issue. All of my audio drivers are up to date, my sound mixer and system sound settings are as normal as can be, and there is nothing anywhere in control panel to suggest that something has gone wrong. The computer seems to me convinced that everything is proceeding as normal. I would have assumed that it was an actual physical issue with the speakers themselves in that case, however, (and this is the very strange part) whenever I switch between speakers in control panel, they actually broadcast sound for about 3 seconds before shutting themselves off, so I am truly very lost as to what the issue is. Knowing me its likely something very basic but I cant find any setting that would cause the computer to voluntarily turn its own sound off and act like it isn't, and the internet so far hasn't been of much help either. I'm new to owning PC's and I'm hoping this forum can help me locate the source of this problem. I am on a LENOVO Legion 5i running Windows 10 Version 1909.

Thank you for answering steve108. I have tried the windows sound troubleshooter and it came up blank. Doesn't seem to be any sign of errors in Device Manager at all either. As for uninstalling a device, it doesn't seem to be a specific device that doesn't work. The speakers all work fine (in the sense that I can enable them and Control Panel shows that sound is coming out of them) but that doesn't translate into actual real sound for some reason. Especially given that enabling a different speaker (my computer seems to have two different Realtek Speakers listed under playback devices) actually does play sound perfectly fine for a few seconds. As well as the fact that my headphones also will not play any sound either. I'll try anything though so if I was to try and uninstall an audio device, reboot and reinstall it how would I go about that?

It is annoying when the troubleshooter runs reports back that all is well, the problem is that there is no feedback for a problem with a bad connection on a jack point. I had no sound recently, when I thought about checking the sound card etc. Fortunately, I found that the weight of the cable over many years, had caused a bad connection at the sound jack: I made up a support harness from thick copper wire by wrapping it round the bunch of wires entering the back of the PC .