This tweak initiates the User’s logon/startup sequence before locking Windows 7/Vista/XP; thus, speeding up the OS startup process while maintaining the security provided by the login screen.

What it solves: Traditionally, you turn on your computer and wait a few minutes. Then, you log into windows and wait a few more minutes. This tweak eliminates that wasted time by allowing you to turn on your computer, go work on something else for a few minutes, come back, login and begin working immediately because your profile and startup programs have already loaded! It is particularly useful for people who are the sole or primary user of their PC and use the login screen purely as a security mechanism.

I couldn’t find a streamlined step-by-step guide online so I figured I’d put one together myself.  Sources are credited below.

Step 1: Auto-Login on Startup.¹

1. In Vista/7, Click Start, type netplwiz in the search field, and hit Enter.
   In XP, Click Start, click Run, type control userpasswords2
   (This loads the Advanced User Accounts control panel).
2. Uncheck the Users must enter a user name and password to use this computer option.
3. Click Apply.
4. Enter your password into the Automatically Log On dialog box that pops up and click “OK“.

Step 2: Lock PC Immediately after Login.²

1. Click Start -> All Programs, right-click on the Startup folder, and select Open.
2. The Explorer Window opens. Right-click in the whitespace and point to New and click Shortcut.
3. The Create Shortcut Wizard opens. In the text box, type the following:
   rundll32.exe user32.dll,LockWorkStation
4. Click Next.
5. Enter a name for the shortcut (e.g., “Lock Workstation“).
6. Click Finish.

Step 3: Reboot.

Step 4: Enable Power-On Security.

1. Please view your BIOS Security options and enable the power-on password feature. Otherwise, you run the risk of allowing someone to boot to safemode without any password access (as pointed out by a commenter).

1. about.com – Source of Auto-Login steps.
2. microsoft.com – Source for Lock PC steps.