I'm going to write it's likely the security key was changed.
So I'm having a weird *** problem with my wifi. It works fine on my laptop, xbox and the like. But each time I try to connect to it on my windows 8 pc it either says - The network security key isn't correct - even though my password is correct because I use the same one on my laptop and have it saved there. Or when I try to do it automatically using the button on the modem it says Windows can't get settings automatically. Enter Security Key instead.
I've rebooted my pc to factory settings and it still won't recognize my security key.