Start by editing a registry key:
Edit the key named AutoAdminLogon and change the value data to 1
After that, run the command netplwiz and uncheck “Require users to press Ctrl+Alt+Delete”. This option can be found in the Advanced tab.
Once you hit Apply, you should be greeted with a new form:
Fill this out with the account details for the account you wish to auto logon. Voila.
On a few occasions, the last window prompting you to enter user data hasn’t shown up for me, and I’ve been able to remedy it by ticking “Users must enter a user name and password to use this computer” on the Users tab, hitting Apply, and unticking it again, then hitting Apply again.