Try to provide some more information so we can help you more effectively.
How old is the computer? is it a mass produced system? if it is then it may have a system recovery solution, so you could wipe it and take it back to factory settings.
Try tapping F8 when you power up, this will display the boot menu. Then select "Last known Good Configuration" and see if you get any further with that.
What password cracking software were you attempting to use?