This is complete rewrite of an earlier post in which my purported solution to my Wi-Fi woes turned out to be ineffective. The specific problem concerned only certain networks, specifically the Wi-Fi in my Singapore hotel room and the Wi-Fi at Changi airport. The former required a password and my smartphone connected without a problem but my laptop seemingly connected without needing to supply a password. However, while connected to the Wi-Fi, my laptop would not connect to the Internet. At Changi, I likewise connected to the network but couldn't reach required site to insert my 5 digit password.
A suggestion provided on Tom's Hardware site at least solved the problem at Changi. Open System Preferences under the Apple logo and choose Network:
The suggestion was to click on minus sign in the diagram above while Wi-Fi is selected. Once the Wi-Fi option is deleted, restart the laptop and go back to above screen and click on the positive sign. Choose Wi-Fi from the drop-down menu and then try connecting again. It worked for me. This is something that I'd never tried before but I've now added it to my troubleshooting armoury.
