How can I overwrite the hosts file in Windows 7?
Solution 1:
If you're logged in as an administrative user, that's not enough. You will need to right click on the Notepad icon and select Run as administrator.
Solution 2:
You can right-click on the hosts file and click Propeties, then Security. Add your username to the security group and give yourself read/write permissions. Click Apply and you will be able to save your new settings.
But when you finish I advise you to remove yourself from the security group to prevent any unwanted changes done by others.