How to fix driver and connection issues.
If your Arduino Uno isn't showing up in the IDE: 1) Try a different USB cable — many cables are charge-only and carry no data. 2) Install the CH340 driver if you're using a clone board. 3) Check Device Manager (Windows) for a yellow warning icon under Ports (COM & LPT). 4) Try a different USB port, preferably directly on your PC rather than through a hub.