rebooting

I am having problems with Vista. i Installed with dameon tool and opened with xp home. install went fine. I did have problem with dideo display i switched to NVIDA Getforce fx 5500. Now it says to turn kernel debbuger off. I do not know how to do this. I tried to delete dameon tools but it will not delete. When i go to phots ,documents my computer reboots! I did a upgrade install. I also have a program Picasa 2