Automatic Windows logon as a predefined user is a convenient feature for single-user machines or home computers. This removes the hassle of unnecessary repetitive password entering in a secure environment and speeds up Windows startup and user profile warmup.
Howsoever, please do never forget that this is a kind of a security breach and should never be applied on computers, which could fall into hostile hands.
Let's do it, or at least test the chance and revert if inadmissible. This is the simple and non-hazardous way without the risky messing-up with the Windows registry.
- Find the User Accounts screen: Depending on the Windows version this could be Start > Run > control userpasswords2, or just Start > control userpasswords2. If none of those work open a command prompt window using Start > Run > Cmd, or just Start > Cmd, or Start > All Programs > Accessories > Command Prompt, and then type control userpasswords2 and press Enter. On Windows 8 just search for and execute netplwiz.
- Position yourself on a user who will be automatically logged on, uncheck 'User must enter a user name and password to use this computer.' and hit OK or Apply.