how to update laptop bios?

You must only use the BIOS update (if one exists) that's supplied by your laptop maker on their own website.
Instructions on how to apply it should be either on the download page or as a text file included with the download package.
Go here: http://www.sagernotebook.com/index.php?page=support

Edit: I've just checked all the available downloads for your NP9130 and all they have are driver updates, no BIOS updates that I can see.