Must get past security

Security Manager has me locked.out  just bought the latitude yesterday .

The guy showed me it was all access.

Hit home and security manager has me.locked.out and I must provide a password.

I have been to the password sites 

And a few times to the bios-pw site 

When I enter my code in order to retrieve a free password it only gives me. A serial number marked "old" which is rrrrr9nn 

This does nothing. Went through a list of.ppossible passwords I cannot access anything until I get past thos hurdle

.. I've tried restart with every F key and cannot get to the reboot screen lmk what you find out 

Service tag 

thank you for your help