White screen, asking for system password

Hello,

I have a weird one for you. My computer was fine yesterday. This morning, I went to turn it on and it began as usual with the Dell screen where it gives you the F2 or F12 option and then all of a sudden, instead of booting up, it goes to a white screen that says something to the effect of : This computer and data within is password protected. Please enter the system or administrator password. However, the the only keys that have any effect on the computer are the enter key, which just makes the computer say the password is invalid and the esc key which shuts the computer off.

Does anyone have any idea what this is or how to fix?