Apple laptops go off line.

Hi there,
I have an iBook G4 and a MacBook 2.2 both were doing fine, wirelessly going on line. Suddenly without any known reason, this morning, they do not go on line.
No changes were made, no software was downloaded or anything else I could put my finger on.
I ran the diagnostic teston the MacBook:
All the things from Airport to three or four down the list show a green spot, except the last two: Internet and the server, which have red spot .
My broadband is working on my PC. In fact I am using it to write this message.The PC is not wireless, it is connected by wire to the router.
Any suggestions.
Will be very grateful.
Thanks

Interference

Plug your laptops in direct and check.

Try resetting the wireless modem.

Move the modem closer to your workstation.

I have had luck with all of the above. My neighbor must have bought something recently as my signal went in and out at will. Driving me crazy. Picked up a splitter and extra cables and moved the modem upstairs and now it's all good.