You’re at the logon screen. The server says “Automatic restart will occur today”. If you log on, it will either restart now, or when you’re finished, and you’ll get some support calls when it’s down!
From your favourite remote support tool, run the following command *before* logging on:
reg add HKLM\SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate\AU /v NoAutoRebootWithLoggedOnUsers /t REG_DWORD /d 1 /f
If you leave the password prompt (click back to the Ctrl-Alt-Del screen), and then go back to log on, you should see that the “Automatic restart will occur today” part of the warning is gone, and you can safely log on.