ALT+TAB, CTRL+ESC, CTRL+ALT+DEL

{If you wish to disable those keys while your

application is running call SystemKeys:

When you call SystemKeys, if Disable is True,

the keys will be disabled, False otherwise.}

procedure SystemKeys(Disable: Boolean);

var OldVal : LongInt;

begin

SystemParametersInfo(SPI_SCREENSAVERRUNNING,

Word(Disable), @OldVal, 0);

end;