Due to the ease at which laptops can be stolen, you will need to contact Dell Tech Support and prove ownership.  Once that is done they will provide you with a Master password to unlock the system.  You can click here for a Dell FAQ on the topic.

witch latitude is it?

 

if its a older model then you have to reset the bios bye removing the batt on the motherboard.

 

if its a newer model then you will find the ansaw on your hardisk =)