The screen you wrote about is the BIOS password completely unrelated to any Windows password.
For reasons related to laptop thefts this password on most laptops is a Dell or factory only reset. Go to Dell.com to find where and how much it is to fix this.
HELP PLEASE! So, I've ran into this unusual difficult problem with my Dell Windows 8 Laptop. It has some hard drive password on a black screen it demands for to login to the laptop. Reason being is because my mom forgot the original password for the account user. Somehow she thought creating this would solve that issue but now it's a bigger issue. ALSO.. I have a Super Multi Drive Install Disc compatisvle for windows 8.. would this be any use ? Nothing happens when I insert the disc though.