What the . . . ?

Ow! Ow! Please stop twisting my arm! OK, I give up. I'll install Win 10.

So I did. All seemed to be well. However when I power up on the Dell Inspiron laptop, it comes up with the following deathless message:
A Connexant audio device could not be found. The application will now exit.
closely followed by the following splendid piece of gobbledegook:
Failed to initialise MainWindow Exception has been thrown by the target of an invocation.
Hitting OK in both cases seems to put whatever that is to sleep again, and I can proceed.

Something to do with SmartAudio? Laptop has a couple of Logitech speakers attached.

No such prob installing Win 10 on the Dell XPS desktop, which also has a couple of external speakers.

Any thoughts please?

Does this bit of reformatting make the message more understandable?

Failed to initialise MainWindow,
Exception has been thrown by the target of an invocation.

Regret not! There was no comma in the original.

Translation then

Some sub-system or app could not open its window,
So it got over-heated and threw a strop

Thanks for putting that in English!

Presumably one of the startup apps has thrown a wobbly.

So how do I now find out which so it can be deleted?

Disable all of them and check that the OS boots. Then enable them one at a time, checking each time, until you get the problem. Then you have found your culprit. From your initial post it's something to do with audio.