Here is the issue:
I tried updating the BIOS using one of HP's software downloads, and even though it exited successfully, my laptop does not boot. Nothing loads, and the screen remains black. I have tried resetting the CMOS battery and tried to recover from a USB drive with a HP_TOOLS partition that contained the UEFI Support Environment. My laptop doesn't have the HP_TOOLS partition since it got deleted when I reinstalled Windows.
The laptop is a HP Pavilion DV7 4190US. What could I do? In addition, my sister has the exact same laptop as me. Is there something I could use from her working laptop to recover mine?
EDIT: I forgot to add that I have also tried extracting a BIOS .bin file from the HP BIOS Update software downloads using Universal Extractor and putting it in a USB drive. This does not work either.
EDIT 2: The problem has been solved. When I tried using the other BIOS, it was giving me the "… BIOS no fully ACPI compliant." blue screen. I downloaded the HP Support Environment (link) and installed it to the USB. The BIOS that I took from my sister's laptop was still in the USB once the installation was done. Once the USB drive was ready, I inserted it in my laptop and followed Moab's procedure (Win key + b pressed until the screen pops up). The BIOS recovery tool appeared and after that, I just had to follow the instructions
My laptop now works. Thank you so much for your help. Now I need to learn how to do BIOS updates properly.
Best Answer
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.