wireless

today i have had virgin media installed and we have a scientific atanta 2100 router to connect to the broadband i am unable to connect to the internet via wirless router.The following routers i have tried
linksys wirless g broadband router,the model number is wrt54g v5 and also TP-LInk TL-wr642g
both of these i am unable to connect to the internet with
any solutions?