How to Block websites from accessing.

Requirement:
This can be done if you are giving access to someone else to use your personal computer. since you don't want them to access any site which you wanted to prevent accessing from your PC, you can go through this.
It is the simplest and advanced way of blocking site instead of using some third party application to block such.
To Do:
Open CMD / Command Prompt
Type: "notepad c:/windows/system32/drivers/etc/hosts"
When pressed enter after typing the notepad window pops up with the hosts file's details.
or the other way to open is open "C:\WINDOWS\system32\drivers\etc"
here drag and drop the "hosts" file into a notepad.
here locate the line "127.0.0.1 localhost".
To Block a website e.g.: google
type below the line "127.0.0.1 localhost"
127.0.0.1 www.google.com
127.0.0.1 google.com
127.0.0.1 www.google.co.in/uk/za etc.....
127.0.0.1 google.co.in/uk/za etc.....
Save the file(do not save as anything or it wont work)