When starting Windows 8 you’ll see the Metro logon screen as shown in the picture below.
The user logon then looks like this.
If you prefer to get the Windows 7 style logon screen back, set RPEnabled to 0 the key is stored under
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer
The next time you logon the Metro style will be gone and you get back the classic logon screen.
By the way if you want the classic start menu back I suggest you read How to Enable Good Old Windows Vista and 7 Style Start Menu and Disable Metro UI in Windows 8 Developer Preview?