autorun

how to launch automatically at startup secure lockdown

Your question is vague, but, when enabled, Secure Lockdown automatically starts the "Master Application" upon Windows startup.

I want secure lockdown starts automatically as soon as I press the start button on my computer. Without user selection.

By enabling Secure Lockdown, it will start automatically when Windows starts.

when I check Enabling Secure Lockdown

the computer restarts and I have to choose which user account I want to open

But I want that when I turn on my computer, I do not have to choose a user name but arrived directly on lockdown software.

Is that understood

You  are referring to WIndows Auto Logon. You can find instructions on how to do this here: http://pcsupport.about.com/od/windows7/ht/auto-logon-windows-7.htm

thanks does it work

But now (alt shift s) do not work

How do I disable lockdown??

If you had anti-virus software running, It is blocking the Secure Lockdown configuration utility from running, thus the Alt-Shift-S key sequence is not functioning. Hopefully you have another admin account on the system so that you can delete the locked down account and start over. If not, you will not be able to disable Secure Lockdown and you'll need to re-install the OS.

:(