If you have difficulty connecting to a wifi network you are sure that you should have no trouble logging on to, consider folllowng these steps to the remedy the problem. This worked for me tonight when a laptop running Windows 8 didn't connect to a wireless network - I wasn't even prompted for a password.
Open device manager - you can find it with a simple Windows search.
Locate the wireless network card in the Network adapters section. Right click on it and select uninstall.
3. Restart your PC. Windows should detect the card and automatically reinstall it.
This trick got me back online and working tonight.