I have a HP650 notebook (Windows 8.1) and have for about 20 months. I ran a battery check and it said to calibrate it so i did so by going into the HP diagnostic test or something by pressing F2/escape on start-up. I ran it fine and it went for about 2 hours and upn completion it said it worked. It then restarted the laptop and i got a BSOD. It read "Your PC needs to be repaired. The boot configuration data file is missing some required information. File /BCD . Error code:0xc0000034. You'll need to use the recovery tools on your installation media." After looking online for a couple of hours someone told me to run an elevated command prompt and type in the following in order: "Bootrec /fixmbr, Bootrec /fixboot, Bootrec /scanos. Bootrec /rebuildbcd". After doing so it worked and i backed up everything on my laptop. My question is why did this happen. It must of had to been something to do with the battery configuration. Anyway, how can i stop this from happening in the future? Will it happen again or is it fixed as i typed those specific commands above and it worked or are the commands just a temporary fix or something? Also can i run the battery check again just to double check it worked or do you think i will get the BSOD error message again?