Wifi and internet connection

Registration date
Friday May 31, 2013
Last seen
May 31, 2013
Hi last week our internet on our desktop computer stopped working and so did the wifi. We disconnected the Wifi and called our internet provider. The modem is fine and the internet is up and running a gain. But when we reconnected the router for the wireless our internet stopped working(it says that the dns look-up failed when chrome is opened) and the wifi also does not work( when i am on my phone it has the wifi sign and everything seems to be fine but is says cannot connect to a network) I have tried resetting the modem already and we cannot seem to figure out what the problem is please help us
Thank you