Sony Laptop - Black Screen with a Cursor

Hello,
I have had my Sony laptop for about two years. Sunday night it was working perfectly; that night I shut the computer (I admit I did not shut it down like I should have) and left it off the charger (I probably should have put it on the charger...) My computer cannot stand five minutes without the charger.... Anyhow, so the next day, I turn on the computer, but it doesn't turn on! It shows the Sony screen, the the Mircosoft starts to boot, and before it goes to the green/blue page where I can imput my password and access my computer, the screen remained black! The cursor is showing, the keyborad is responsive, my computer even signals that the battery is fine.... Then I realized I hadn't put in the charger, so I did that. And it didn't work. I have taken the battery out. I have taken it out, pressed the power button, etc--with no result. I have turned it off and on--I get the same result... I have done the ALT, CLT, DLT and THAT doesn't work. I have a Psych paper due in a week. I'm desperate, please someone help me...