Ok open your windows explorer and go to C:\windows\system32\drivers\etc\ (assuming you have a default install).
Originally Posted by hypermode
Now with Vista and above this file is normally locked from editing by default. Right click it and uncheck read only (might be some permissions you need to change 2 but not sure I can edit mine like this :P). Then double click it to open it your being prompted for a problem to open the file with pick notepad/wordpad. For every hostname you want to block add a line like this and replace HOSTNAME with the hostname to block (forums.wow-europe.com for example):
Once your done for every hostname you want to block safe the file and check read-only again.
P.S. If this breaks anything undo the changes you made .