Computer won't connect to the Wi-Fi?

I have a Lenovo laptop with windows 8 and I have recently got a new Wi-Fi because my mom switched providers and I used to have no problem and now that we have the new Wi-Fi it won't connect to it and it says that I'm still connected to the old one even though we don't have it. When I try to connect it to my new Wi-Fi it says the settings saved on my computer for the network do not match the requirement of the network. I don't know what to do, Help!

First, have you "scanned for new networks" in the Wi-Fi settings? Is the new SSID (the name that appears on your Wi-Fi setup on your computer) the same as the old one? If it is the same Go to manage networks and delete the OLD setting. Then reconnect. You will need the correct password!
The new password may be written on the new router if a new one was installed. If not you may have to check the paperwork or call the new ISP!