My Toshiba Satellite L305-S5911 won't turn on to the log on page?

my lap top will only turn on and show the toshiba screen then it just shows a black screen with a little white flashing line in the upper left corner. And I been waiting for hours so it can turn on the the Log on page, but it won't show. What does it mean? How do I turn it on again? Do I have Virus?