black screen with blinking line.

Hi, I can't access some of the information required in the post, but I have a Dell Inspiron 1420 that's about 3 months old. I left my computer unplugged for a couple hours and when I came to turn it back on it was stuck in a black screen mode with a blinking white line in the left corner. I tried restarting and ctrl-alt-delete and all of the other buttons but it keeps going back to that mode (and it's plugged in, so it shouldn't be a battery problem). Is there a way that I can catch the computer while it's in the Dell loading screen (using an F-key maybe?) before it goes to the black screen? Sorry, I'm new to PC's so hopefully this is an easy problem!

Thanks.