There are two different hosts files that you may need to work with
First:
c:\Windows\System32\Drivers\Etc\Hosts
Second
c:\Windows\System32\Drivers\Etc\Lmhosts
If you have a LM hosts file try and rename it to lmhosts.bak or something similar
When you have added the information to your hosts file try and clear out a few networking components by running the following commands
ipconfig /flushdns
netsh int ip reset resetlog.txt
Those two command should cause any issues to be flushed from your DNS cache.