Internet connectivity issues

My Inspiron E1505 connects to the wi-fi just fine but a message pops up saying 'There is an IP address conflict with an other system on this network.' But even when it doesn't say that, when I open Internet Explorer, Google Chrome, and even Firefox, it says 'Can't connect to the internet' I payed the internet bill, but that didn't fix the problem. Could someone help me out? I'm thinking that I should reset it to it's factory defaults. Should I?