I am encountering the same message ("No audio device detected") on a brand new Dell tower unit - not a laptop. My IT guy tried everything in his bag of tricks to no avail. After several hours and several hundred dollars of his time, the workaround he came up with was for me to purchase a "Sound Blaster Play! 3" USB dongle, plug that into the tower unit, and run the speakers from that - bypassing the internal sound card altogether. It works, but it's galling, to say the least. And for all of you with laptops, it's not going to help. Sorry.
Here's a link to the external device.
https://us.creative.com/p/sound-blaster/sound-blaster-play-3
Note to interested parties: My platform is not a laptop it is a Mele Mini PC and I was not using external speakers per se, I was using my TV/monitor with an hdmi cable connecting the PC to the monitor. This worked fine before I accepted upgrading from Win10 Pro to Win11. Now only the video works, the audio keeps saying no audio device connected, no matter what. Also, I have a second identical PC that I did NOT upgrade to Win11, that one is still on Win10 and working fine audio and video via a separate hdmi cable to the same monitor. Personally, I've given up trying to fix this. When I want sound, I use the Win10 PC; I use the Win11 PC only for storage of Research materials that don't require audio playback. Long story short: Microsoft has screwed us. If anyone is bold enough to start a class legal action against MS over this, you can count me in.