On my troubled Acer laptop I changed the name of the administrator user to my name and added a strong password. Then I created a standard user account for the kids with no password and automatic login.

Configure Vista For Automatic Logon

To do so, click Start and type netplwiz in the Search field and then press Enter. Click Continue when the User Account Control window appears. From the User Accounts window that appears, verify that your own user account is selected. Clear the Users must enter a username and password to use this computer option and click OK. Provide the password for your user account when prompted and restart your computer. Vista will automatically log on with your user account.

Microsoft also has an article on how to do this called Turn on automatic logon.  The instructions are almost exactly the same except Microsoft suggests enter control userpasswords2 in the Search box. This program requires authentication unlike netplwz.

To turn off automatic login just check the Users must enter a username and password to use this computer option.

Related posts:

1. Windows Vista Revisited
2. Redirect to Login in User Permissions Plugin
3. Windows is unable to connect to the selected network