Help please with 2 ibook G4

hi all first time post here

i could do with some help
i have just be given to iBook G4 both of them are running 10.4
i have the same problem on both i can connect to the internet on both though the ethernet cable(i am using one of them now to type this post) but some strange reason the wifi is playing up.
i can connect to netgear router with both ibooks fine and get ip address for both (eg 192.168.?.?) but when i go on safari

Safari can’t open the page.
Safari could not open the page “http://google.com/” because the server stopped responding.

could any one help with this please it would be a great help and thank you for your help in advance

yeah i have tried that it tell me that the internet is working fine