I bought a couple of UNOs a year or so ago, the type that have a tiny USB socket and a permanent surface mounted ATMega 328. I’ve only now needed to use one instead of my regular type. But neither can compile any sketch. The error lines are a successive series of (to me meaningless) messages about syncing. Another clue is that the port in use refers to CH340, but I confirmed that the drivers for that are installed.
Before I experiment further and risk making things worse, could someone show me how to proceed please?