1. Click on Start and then enter the following command in the search box netplwiz Press the ENTER key
This command will load the Advanced User Accounts Control Panel applet.
2. In the Users tab, uncheck the box next to Users must enter a user name and password to use this computer.
3. Click on the Apply button at the bottom of the User Accounts window.
4. When the Automatically Log On dialog box appears, enter the user name you wish to automatically login to Windows 7 with. Then enter your account password in the two fields where it’s asked.
5. Click the OK button.
6. Click OK on the User Accounts window to complete the process.
From now on, when your PC starts up, Windows 7 will log on automatically.