Ok here is what you do i tested it on Win 7 and it works as i used it on Win XP so wasn't aware that it still worked.
You go to this C:\Windows\System32\drivers\etc
And there will be a file named hosts there are two files with that name the one without the extension is what we want that is hosts & hosts.msn. We want the red one.
You then open it with notepad and at the bottom you will find something like this:-
Code:
127.0.0.1 xxxxxxxxxxxxxxxxxxxxxxxxx
127.0.0.1 xxxxxxxxxxxxxxxxxxxxxxxxx
127.0.0.1 xxxxxxxxxxxxxxxxxxxxxxxxx
So say you wanna block TWC so you do this change and save it (you can only do this if you have admin rights to edit the file).
Code:
127.0.0.1 xxxxxxxxxxxxxxxxxxxxxxxxx
127.0.0.1 xxxxxxxxxxxxxxxxxxxxxxxxx
127.0.0.1 xxxxxxxxxxxxxxxxxxxxxxxxx
127.0.0.1 www.twcenter.net
After saving the changes you restart your PC and then voila it doesn't opens in any browser.
Hope this helps.