Open the registry by clicking on Start --> Run --> Then type Regedit and click OK.

 

Navigate to the following key.

 

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\SpecialAccounts\UserList\

 

You will create a new key of DWORD Type specified as "REG_DWORD" below.

 

Name the new entry the username you would like to Hide.

 

Then Set the value to 0 which is the default.

 

Below in the example you can see the ASPNET user is already set to 0 which is why it's not visible when you login to your computer.

 

This process can be used to either turn on or turn off hidden accounts.