program block computer on full screen games

defence+ used with maximal defence, block completelly computer (ctrl+alt+del not works)
aufcours computer still works, but i see only blank screen

when starts full screen games (half-life, counter strike)
game change resolution, i think next must be
defence plus window to accept/reject but nothing only blank screen

many times forget disable defence+
i must reset computer
disable defence+ then start game

vista 64bit, q6600, ati 2600xt
problem wasnt on xp 32bit

Put D+ in Training mode, enter the game, play a little, quit game and put D+ back on it’s previos settings.