You will need to check the wireless settings of the router.
If your network is secured then make sure that you are typing the correct network key.
also make sure that the DHCP server is enabled on the router.
is there any computer connected to the router ?
If yes then you can open the router set up page on that computer.
Router set up page is the page where you can check all the wireless settings of the router.
Click here for step by step instructions