Recently my IP upgraded me from Coax Cable to Fiber Optic.  Everything on the main computer works great.  Problem is when I try to establish a Wi-Fi connection on my other computers, I can find the new router but am informed the security key is wrong.  It is the same key that was used for the main computer.  How can I fix the problem?   And I cannot find a way to reset or replace the key on the main computer.  Thanks, Mindblower!

Problem is resolved.  Rechecked the security key I wrote down and there was a mistake with one of the letters.  Cannot remember how many times I verified the security key and this time saw the error.  Thanks anyway, Mindblower!