Problem solved by resetting windows. Hate being driven to such extreme step!  
Hi, I have purchased a baseus 140w USB-C charger, since Dell 130w adapters are so expensive and keep on failing after less than a year (already 3 discarded!). Chargin works fine on my Dell XPS 9570. However, when I plug in the USB-C charger, computer screen flickers birefly as if I had pluged in an external monitor. Moreover, when I plug in the charger, it also kills my HDMI connection and my external display. Thus I cannot use the two peripherals together, which is a pain.   Any ideas?   Many thanks  
XPS 9570 HDMI USB-C conflict