I write this solution to you, so that you not make the same mistake.
Because I’m a radioamateur, I have a CW key and would like to connect it to my computer with a CW Keyer. The solution for me was a NanoKeyer with a Arduino Nano board inside.
And here was my problem - I bought the chinese version with CH340 chipset.
Don’t do that - because Windows 10 then can’t go to sleep. There is a failure in the CH340 driver, that prevent the USB port for power saving or somthing else.
My adwise is to buy the Nano with the FTDI chip for USB, and your computer can now Sleep.
This is only a problem when it is connected to your computer all the time with USB
Best “sleeping” OZ7LM.