Remove primary password from BIOS?

I recently acquired 3 Dell Latitude C610 laptops from a surplus computer store that sold them for parts. I have been able to restore 2 of them and donated them to Hope Industries in my community. The third laptop I am having a hard time with.  I have been able to acquire a Master password for the BIOS and am able to access the BIOS setup and would like to remove the requirement to input the master password every time the laptop is turned on.

When I try to remove the password I am asked for the OLD PASSWORD which I don't have. When I type in the Master Password into the OLD PASSWORD it immediately tells me it is INVALID.  Is there any way to remove this password when I don't have original password? A software perhaps or a procedure that would allow me to delete this password?

Any help would be greatly appreciated.