I forgot that most ISPs only have one DNS server and that all subscribers get the same one. Those few ISPs that do have more than one server always update their servers all at the same time. :lol
Whatever man....
So what else did you do beside the DNS Flush to make sure that it was an IP block again? Did you try going to the IP of the site? Did you try using the same DNS Servers that your wife was able to access the site with? Did you change the MAC address of the computer you were using to try and get a new DNS, Gateway? Or did you just call Comcast with this know it all belligerent attitude?
I'd bet on the latter.