This can be disabled from the LocalSecurity Policy snap-in or from Windows Registry.

To disable displaying the Las Logon ID in Windows from the Local Security Policy:

1. Click Start – Control Panel – Administrative Tools.

2. Open the Local Security Policy object.

3. Expand Local Policies – Security in the left pane.

4. Double-click the “Interactive Logon: Do not display last user name”

5. Select Enabled, Click Apply & OK

6. Close the Local Security Policy Editor

Restart the computer and you should no more see the Last logged in username.

To do this from the Windows Registry,

1. Click Start – Run, type “regedit”

2. Navigate to

[HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Policies\System]

HKEY_LOCAL_MACHINE
\Software
\Microsoft
\Windows
\CurrentVersion
\Policies
\System

3. In the right-pane, look for the key “DontDisplayLastUserName” and set it to “1″

4. Close Windows Registry Editor and restart Windows.

Last Logged in user name would have now disappeared.