The Problem

You want to change the data in a windows system file like "hosts" but when you try to save it in notepad, it says that you don't have permission to change the file. Windows 7 won't let you change the permissions on the file.

The Solution

 Go to the start menu, find notepad, right click on it and select the second option, "Run as Administrator". You now have complete freedom to edit any file, proceed carefully.