Editing hosts file on Windows 8

You have to run Notepad++ as administrator. Otherwise you won't have the neccessary permissions to edit that file.

If you actually have administrator rights, then you're probably fighting against UAC. Make sure to launch your favorite text editor by right-clicking on it and selecting "Run as administrator".

I had the same case, and couldn't change the hosts file even after I checked if I had all the permissions in the user settings or the hosts file's permissions.

ANSWER: Some antivirus software (in my case AVIRA)blocks everything in changing hosts files in their security options. Disable it for a minute, and change. Be careful, it can be risky!