You have a lot of stuff in the chain. Have you isolated which of the connections you cannot make? The error message you quote is ambiguous. For example, can you ping your access point, but not get through the router? Are other computers connected successfully? Can your laptop join other wireless access points? Are you sure all security settings are disabled? One setting people sometimes overlook is setting the access point to accept only specific MAC addresses. Another idea is to turn on broadcasting of your SSID to help your PC find the access point. When all else fails, have your local power company disconnect your power for 2 hours. It’s the very best reboot.
A final idea, your access point might be auto-sensing the (wrong) band based on some other computer. Try turning all your other computers off. Then check the access point to make no computers outside your house are accidentally connected. :o