Hi @CPeter   

Thanks for reaching out to us. 

Please check if your windows7 can connect to other Wi-Fi, such as your neighbor's WiFi or your phone's hotspot?

If not, issue most likely lies on your windows7. In that case, please contact your windows support. 

If your windows7 has no problem connecting to other Wi-Fi, please refer to below guide to remove TP-LINK-456 this profile on the computer  

How to remove the existing wireless network profile in Windows 7

After that, please try to connect to TP-LINK-456 again and see if it will work.

And since this model is specially designed by service provider, it is suggested to contact your service provider for further assistance if the issue can't be solved.