hi i have problems with my iMac g4 all in one

hi i have problems with my imac g4 all in one ive installed a airport card and its running fine but when i try to connect to my wirless router it connects but i still have no internet,it tells me it cannot find server,im with utility warehouse

has the airport card got its own secruity???????if so how can i disable it????or do i need a dongle??

or would it be best to get hold of utility warehouse

i have another mac running on it and my iphone and an android pad so the g4 is the only one thats not

please help some one as i would like to sell it to a friend who in need of a computer but needs it to be wireless

ty