Network popup prevents configure or connect to wireless network. PowerBook G4 Mac)S X 10.4.11

Background info: Laptop is Mac OS X 10.4.11. Laptop was originally set to new wireless network by new Internet provider as was my iPad. I haven't used laptop in a month or so.

However, when I tried to access Internet last week on the laptop, I received the following pop up window, which then prevented access to the window below which has the Network function to configure or connect. I've called Internet provider twice and they say it is an issue with my computer since my iPad can access the Internet.

Network pop up window:

Your network settings have been changed by another application.

When I click OK on that network pop up window, it automatically comes back before I can access the Network window below to manually configure/connect to my wireless network. That pop up window will not allow me to access Systems Preferences, Location, Network.

How do I manually connect to my wireless network when this network pop up window prevents me from accessing any network functions?

Thank you