Does anyone know why I get a black screen at startup on Windows XP?

I turned the laptop on this morning and I am getting a black screen with cursor on top left. I have checked the BIOS setup and it says it is booting to hard drive. I have left the screen up for 1/2 hour and it is just sitting there. I’ve tried to get to a SAFE MODE start-up but it doesn’t respond to any keys. Any help is appreciated.