try this ...........
Auto logon to user account in windows
Step 1. WIN+R (Run) type "CONTROL USERPASSWORDS2" and hit enter.
Step 2. Under the Users tab. Uncheck "Users must enter a user name and password to use this computer."
Step 3. Click Apply. It will have a window pop up "Automatically Log On".
Step 4. Enter the username and password(confirm password also) and hit ok