When I install the Microsoft .NET Framework 1.1 on a computer that is running Windows XP, and then you start Windows, the Welcome screen appears. This screen prompts me to click your user name to start Windows.Why?
When you install the .NET Framework 1.1, a hidden local user account that is named ASPNET is created. When you start Windows, Windows treats the ASPNET local user account as an additional user account, although the ASPNET user account is hidden. Therefore, the Welcome screen appears and prompts you to click your user name.
For more details refer KB 827072