[Kheldar]

set your dns manually (ipconfig /all to work out your isp's dns server)

and put in another providers dns server eg 203.12.160.35 (tpg's dns server)

so you'd have 2 dns servers (i have four assigned by my dhcp server but my firewall is more adavnce than yours - its in my sig)

if its just a dns failure this should fix it