Type "Run" into the start menu search field.
When the Run Line application opens, enter the following into the text field - notepad c:\windows\system32\drivers\etc\hosts
The hosts file will open, and you can edit and save your changes.
The most common reason for needing to edit the windows host file is to test a website on our servers before changing the 'live DNS' to complete a migration. To do this, you should add lines as shown below:
Replacing 'x.x.x.x' with the IP address of your service with ourselves, and mydomain.com with the domain for which you wish to override the 'live DNS'.
Remember to remove these lines once you have completed the testing and migrated!