Dell C840-Laptop Boots to Black Screen SomeTimes


In Runtime
My dell c840 will Sometimes boot to a black screen....It will go to the Boot Screen but not any farther...just shows up BLACK no sound or nothing... after a restart or 2 it will for fine by slecting "last working Setting" or "start normally" but will boot, Most of the time it boots fine! Performs fine and all, but when the black screen comes up its annoying...Any idea? ty :)