Disable welcome screen and fast user switching

You can disable fast user switching by going to gpedit ...

Administrative Templates -> System -> Logon -> Hide entry points for Fast
User Switching = Enabled

Navigate to "HKLM\Software\Microsoft\Windows\CurrentVersion\Po licies\System"
Create a REG_DWORD "HideFastUserSwitching"
Value 1 turns it ON
Value 0 turns it OFF

found that answer to have a single user logon screen.

Administrative Tools_> Local Security Policy
Then go to the Security Settings -> Local Policies -> Security Options and
in the right hand pane find the "Interactive Logon: Do not Display last user
name"

Enable that policy and logoff and give it a try.

Someone else mentioned if you want the control-alt-del behaviour go to start
then type: "control user passwords2". On the main tab you can require users
to enter name and password (not sure if that is required for the first thing
I mentioned to work). On the advanced page you can find the option to
require ctrl-alt-del.

> Navigate to "HKLM\Software\Microsoft\Windows\CurrentVersion\Po licies\System"
> Create a REG_DWORD "HideFastUserSwitching"
> Value 1 turns it ON
> Value 0 turns it OFF