please help. windows will not boot at all on my dell desktop computer. i am running windows vista. it will get to the screen thats says microsoft corporation and then stops. have to push the power button to turn it off. it does this on all the command prompts and when get to the screen repair windows or start windows normally it will not go to the repair and does that on all prompts also. tried to reinstall windows with the reinstall disk and it says no bootable device. so i dont know what else to do.