@Kevin_Z Thanks for your reply. Extender is showing 3 LEDs. I connected by ethernet OK. But when I tried again to enter the wireless password into the dialogue box of the EXT it still did not...

Just connected extender to my router, plugged it into a power socket and it is showing 3 bars - all set to go. When I search for it on my PC, it is present, with EXT after the name of my router. But...