How can I recover from a corrupt BIOS in a HP laptop?

You may have to unhide hidden folders in Folder Options on your sister PC before starting.

On Your sisters PC, access the HP_TOOLS partition (assign it a drive letter in disk management) and open the "Hewlett-Packard" folder, then "Bios" folder, in there will be 3 more folders, copy ALL the files from sis's "Current" folder to your "current" and "previous" folders on your usb drive that has the same folder structure.

Be sure the usb drive is fat32 and has the volume name HP_TOOLS with the proper folder structure, drive letter does not matter.

Connect usb (legacy usb 2.0 port if you have one) with laptop powered off, power up while holding the win+B keys down, keep holding them until you get a bios recovery screen.

hopefully it will crisis recover your bios, some models use the all 4 arrows keys instead of win+B

NOTE: Remove the drive letter from your sisters HP_TOOLS partition when done copying files.