Toshiba L 455D - laptop - can't get past first (BIOS ?) screen.

Hi guys!
I have an old Toshiba L 455D laptop that I really love and would like to just bring back into operation. Windows 7 is what she has installed. About a year ago, after a difficult (meaning unusually slow) shutdown, she refused to let me get past the intro screen. Please forgive me for poor terminology in these matters - I'm quite old (56). The screen that I'm referring to is the one that you set a password for so that no one uses your computer after power-up. I typed in the password as always and she refused to allow me access. I tried a different password input, and got a different style of refusal to enter. This make me think that the correct password was at least received and understood on some level, but access was still not allowed.
After numerous power-up and down experiments, including a battery removal, now when she comes up the only screen I get is the (BIOS ??) screen. It consists of just an inch-wide blue band in the middle of the screen, with the words - "Enter Password" along with an area to put something in. I have no idea what to do now, and no knowledge of possible passwords. Please help. Thank you

Dave Reintzell