If you do EXACTLY what i say, it will be done without any problem.
So. Copy your hosts to desctop
Open it with Notepad
Edit it as you wish
Close/Save it
Place the edited hosts IN to the C:\Windows\System32\Drivers\etc and confirm the replace the original ones in the dialogue will appear.
That's all.
Otherwise go to your control panel and do this:
And after that you can edit your hosts in its original location.