Power Cord Required to connect to wireless at home?

I have a "wierd" problem with my laptop - this only happens at home and never a problem on the road.
At home my Toshiba satellite laptop has to be plugged into the wall outlet to connect to my wireless network. Why?? I have a Netgear router hooked to the modem (Charter cable) and only to one Gateway PC. Other laptops also have to be plugged into wall outlet to connect.

Anyone have an idea of how to get around this?

That is weird. Does it matter which plug? Can you plug in and connect outside your house. The only thing I can think of is that signal is weak and by plugging into the same outlet your hitting the right spot where you get good signal, has nothing to do with the power cord per say.