StylinRed,
In Windows Command Prompt, type in:
Code:
ipconfig /flushdns
For reference, check this website - http://forums.eukhost.com/f15/how-clear-flush-dns-cache-windows-linux-mac-machines-6337/#.UHs6osXA8S4
Unplug modem completely for 5 - 10 mins. Plug back in. See if that works. If it fails, I'm going to side with Jeremy617 on this one. May be that the IP / subnet assigned to you was blacklisted for whatever reason.