New Wi-fi network: how do I avoid having to type router security key each time

[m654321]

I have set-up a new Wi-fi network on the router I normally use. 

LL now asks me for the router's security key each time I want to go on the internet.
How do I avoid this, i.e. having to type in the key each time and instead embed the
security key in LL for auto-logon to the internet?

This problem has not occurred before, as this is the first time I've created a new network
after LL has already been installed. 

Many thanks for any help with this
Mike