** update suggestion : please install the latest 8.1 with updates.. it has almost solved the problem **
its due to graphic driver incompatiblity
Solution : do not install any extra drivers, like i havnt install wifi, bluetooth,cooling audio etc drivers,, they are built-in in windows 8
because it used to load at startup and make system slow which cause black screen,
i am not getting black screen anymore because the login screen comes before the black screen..
i also disabled the unnecessary programs from start up, and starts it manually(as i know i use them seldom e.g. DFX EQUALIZER)
hope it helps u