ok i have this weird problem that when i try to turn on the computer, it brings me to the black screen with allthe options of loading into safe mode, safe modewith networking, last good configuration and start windows normally etc, and no matter which one i choose, my computer will restart, loading up again andbringing me back to thesame screen. so now i have no way of logging on to computer, let alone being able to startup at all. it's just one continuous cycle and it's frustrating. should i reformat my HD? what's wrong with my computer?