if you adjusted your win7 hosts file as administrator, rebooted and are still having the same problem, then it is a MS problem. the hosts file just like the /etc/hosts in Linux tells the computer who the IP belongs to.
ex: a good way to block things like doubleclick.net and what are in the MS world is to put that in the hosts file as:
when the computer, ANY computer, is starting its quarry as to how to resolve a DNS, the very first place it looks is always itself. who am i is what the computer asks. in my example above when a computer is resolving for doubleclick.net that computer will resolve to 127.0.0.1, aka. HOME, aka, itself and look no further. in other words even if the web page has a link to that advertising/spy/malware/bloated site your computer will never actually go there as it believes it is doubleclick.net what a lovely tool.
so if you properly populated your hosts file with the proper IP and URL, and it is still not going to the correct location, then it is your win7 box doing something stupid, but those are rather big IF's