the only way to unlock bios password for all laptops and worked very fine here is :
in the old laptop there is ic bios with 8 pins named almost winbon or mx ...
in the old laptops there is one ic called main you must remove it with hot air and put it in programmer
then download the bios file it must be with extension rom or bin or hex
then erase the old ic and programme it with new file
for new laptops same steps but there is another bios ic it called EC
any further questions leave comment