Well to your comments, I come to the point that you are messed up with the startup logon screen.
Well to solve follow the steps.
Goto Start>Settings>Control Panel>User Accounts>Change the way Users Log on and off and choose Use the Welcome screen.
If you donot find such then follow these steps.
Goto Start>Settings>Control Panel>User Accounts>User Accounts>Change the way Users Log on and off and choose Use the Welcome screen.
At times the option Use the Welcome screen is choosen but still when the computer boots up going directly to the desktop, Windows comes to halt at user choosing. This is because if you installed SQL SERVER, Visual Studio. This in result makes an SQL_debugger account or ASP.NET account which prevents us to automatically choose user and reach to the desktop. In this situation though you wont find the user name at booting but it does exist in background.
So delete the account which is created by installing additional software.
To do so:
Goto Start>Settings>Control Panel>User Accounts>Choose ASP.net/SQL_debugger account and delete, and choose save files and folders.
Volla! you are done!