Cannot connect Wi-Fi because of previous password

My brother changed the password of the Wi-Fi that I had used to connect my laptop. When he left to another city he changed the password of the Wi-Fi. I know the password but I'm unable to connect to the internet connection because there is a previously saved password.

How can I remove old password and add new password?

Solution 1:

The best way would be to delete or "forget" the network and connect to it fresh.

To delete a wireless network connection in Windows 7:

1. Start Network and Sharing Center.
2. In the Tasks pane, click Manage wireless networks.
3. Right-click the connection you want to delete, and then click Remove network.
4. In the Manage Wireless Networks - Warning dialog box, click OK.

Source: https://technet.microsoft.com/en-us/library/gg252588%28v=ws.10%29.aspx