Windows display
Second monitor not detected? Prove the connection path first.
Separate a physical connection problem from Windows detection/projection settings and driver state before replacing the monitor or dock.
1. Check power, input and cable
Confirm the display has power and the correct input selected, then reseat both cable ends. When possible, test a known-good cable or another port.
2. Ask Windows to detect it
Open Settings → System → Display → Multiple displays → Detect. If it appears, use Identify and arrange the screens before changing drivers.
3. Check Windows + P
Projection mode can intentionally use one screen only. Test Extend or Duplicate if that matches the intended setup.
4. Isolate docks and adapters
If a dock is involved, direct-connect when hardware allows. One test at a time tells you whether the failing link is the monitor, cable, adapter, dock or PC.