USB ports recognise pen drives but can't configure as coms port!

I have two laptops with exactly the same windows 10 pro installation, both have latest updates installed.

One works fine (Dell D630), the other laptop (Dell vostro 15) does not have 'com ports' visible in the device manager tree. Also, when I install Rockwell RSLinx industrial PLC programming software, and try to set up the comms port to any USB, I get an error message saying 'failed to configure the COM port (the COM port may already be in use)'.

I've tried adding legacy devices in device manager (COM port 3 appears, but has a yellow warning), still no comms port available.

I'm stuck! Any ideas?