Having problems with belkin wireless router

well im not sure what happend with my belkin wireless router just yesterday afternoon it was working fine but like around like 11:00pm i just stopped working and now the modem light on the router just keeps blinking and at first i though it was the modem so i went to exchange it for a new one and it is still doing the same thing so now the only way that it will work is if i just use the modem by its self wich is ok for when i just use the computer but i cant sign in to xbox live so can anyone tell me what happend to the router or let me know if i need a new one