Dns_probe_finished_no_internet

Hello,
my asus g550jk laptop, is showing an error message when I connect to my school network I network. I can still connect to my home broadband when I am at home. works on all other networks (hotspots, home broadband) the school does not provide this kind if it support. I have removed all vpn virtual private networks vpn software and run a full system check with avg 2015. I am trying to avoid a system restore as I don't want to have go through the hassle installing all the old programs. I have tried using the advance system protector but instructions aren't very clear on how to use. I am running windows 8.1 64bit