Source -Windows 7 Resets Taskbar to Default When ‘Automatically Log On’ Is Used.
Windows 7 customers that are configuring their accounts for automatic login will find that the operating system resents the Taskbar (Superbar) to the default configuration, Microsoft said. The same problem also affects users of Windows Server 2008 R2, according to the Redmond company, but customers that are running either of the two platforms now have a solution available to resolve the issue.
Windows 7 Resets Taskbar to Default When ?Automatically Log On? Is Used - A fix is available - Softpedia