Tm-3420 Connection Problem

hi, i have a new tm-3420 3g wireless router, this is the second one, as the first one stopped suddenly, setting up the first one was easy, and worked for about 6 month, the new one, does not matter what i do my lap tops cam see the wireless network but will not connect, i am running xp, same as befor, i have been trying for months now, this has me very frustrated, as we need to share an internet connection, i can only set up via lan, i have confirmed that my lap top wireless is working, hellllllllllllllllllllllp !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!