Problem connecting my Toshiba with a BenQ projector

I connect my Toshiba A215 - SP6806 to a BenQ MP512 projector, and suddenly they enter in conflict, everything vibrates and the computer freezes, sometimes I can fix the problem by pressing Esc, but sometimes it doesn't works, and I have to disconnect the projector, and sometimes I have to reestart the computer. This happens often when I watch something in full screen. But sometimes it happpen when I watch a video and a projection from powerpoint or a slideshow of pictures. I tried to fix the problem by changing the resolution and activating the projection option, but anything of this works. Any ideas?Thanks