Notebook Operating System and Recovery

This is my daughter's laptop that I purchased for her for school.  Last night she did an HP BIOS update as prompted by Windows when she tried to shut down the computer.  But now every time it powers on it goes into a Bitlocker screen that prompts for a recovery key.  I've looked on the Microsoft site, and it suggests the key can be found through her Microsoft account (we never set one up, she just logs in with a local account), a USB drive (we never actually turned on Bitlocker, it must have come with it enabled, so we didn't go through that USB creation process), a printout (same), or a text file (the only text file that could possibly exist is on the hard drive we can't get to).  I am able to get into the BIOS, and it is showing the version as F.10 -- is that current?  Why would a BIOS upgrade trigger Bitlocker?  I feel like we're stuck with rebuilding this machine, but hoping this forum has some other ideas before my daughter loses all her data (extreme sadness).  TIA for the help!