Computer screen is blue, it statespassword required will not allow typing

[jimbo1956]

My Computer screen is blue, it states password required ( blinking) but will not allow typing.
I can not get passed this sage and open computer to start fixing any issue. Ultimate goal is to crash ( erase all data and start over.  What are my steps in getting the computer to open.
 I have pressed the keys F@ and others as directed. I can not even get into a mode desred.
What is my next step. I have disconnected and reconnected , rebooted, turned all electrical off and on.
What can I do next.? What does this mean?
Dell Demensions 4700 Bios Version A03  Windows XP   Intel Pentium 4 CPU 2,80 GZ
Siometime states Keyboard error but I have retrierd different key board with same results
    Thanks JImbo1956

[Geek-9pm]

Welcome!
Computer Hope is the number one location for free computer help.
The forum will help everyone with all computer questions.

Here is some information about password problems.
http://www.computerhope.com/jargon/p/password.htm

Information about chaining a password is found elsewhere because of CH policy.

Contact Dell and they can help you with a password problem.