The router's default login is probably "Admin" (without the quotes) as the Username with the Password field left blank.
The wireless encryption key in my D-Link router is masked with dots so, if you cannot remember what yours was, you may need to create a new key. You would then need to delete the 'profile' in all computers that connected with the old key and go through the procedure to Connect again.
It may actually be sufficient to delete the 'profile' in your wife's Laptop and Connect again, so try that as a first step.
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