Open the following folder and locate the hosts file. Direct editing is usually prevented by the windows OS.
use a Trick overcome this
file path: C:WindowsSystem32Driversetc
take copy of hosts file and paste in desktop or some where else and edit the contents, then save it.
At the time saving, windows ask for a file type so save in all files
After that just copy the hosts file and paste to the following folder
C:WindowsSystem32Driversetc
Windows ask for file replace confirmation,give ok
restart the IIS or apache webserver
OR
1. Open the hosts file by Run as Administrator
2. edit
3. save.