Ok,thanks.

Here's how to show hidden files and folders in Windows 7:
http://www.bleepingcomputer.com/tuto...-in-windows-7/
Could you do that,then Click Start,type Run.Open Run,then Copy and paste
%SystemDrive%\Windows\System32\Drivers\etc into the box,and click ok.

Do you see a hosts file with no extension in there now?