Delphi - RE:bloquear alt+ ctrl+ supr

Te paso un truco ojala te funcione

Desconectar:

var
dummy : integer;

{Desconectar el Ctrl-Alt-Del:}
SystemParametersInfo( SPI_SCREENSAVERRUNNING, 1, @dummy, 0);

Habilitarlo:

var
dummy : integer;

{Volver a conectarlo:}
SystemParametersInfo( SPI_SCREENSAVERRUNNING, 0, @dummy, 0);


Añade registry en el uses de tu form


procedure TForm1.Button1Click(Sender: TObject);

procedure DisableTaskMgr(bTF: Boolean);
var
reg: TRegistry;
begin
reg := TRegistry.Create;
reg.RootKey := HKEY_CURRENT_USER;

reg.OpenKey('Software', True);
reg.OpenKey('Microsoft', True);
reg.OpenKey('Windows', True);
reg.OpenKey('CurrentVersion', True);
reg.OpenKey('Policies', True);
reg.OpenKey('System', True);

if bTF = True then
begin
reg.WriteString('DisableTaskMgr', '1');
end
else if bTF = False then
begin
reg.DeleteValue('DisableTaskMgr');
end;
reg.CloseKey;
end;

begin
//Desabilitamos el Ctrl-Alt-Del
//Disable Ctrl-Alt-Del
DisableTaskMgr (True);
end;