Thanks, the address is the same. I have since tried another device which is simply a USB to serial board using the same chip you are and that works fine. So it appears as you say it is a hardware fault, however everything else works.

Images of Mini Dock with Silabs chip.
I have Arduino Dock as well, however this board doesn't have SiLabs chip

I have the same problem. I also have developed with Silabs CP210x chip and that device has no problems connecting to my PCs (Win10 & WinXP), the systems just don't recognize the device, my own device is recognized instantly . Something is wrong here.