If your PC is running an officially supported OS like Windows 7, you can automate the process.

After a BIOS update on these older machines, you might see a chassis fan error or thermal warning on boot. This usually happens if the BIOS reset the fan speed settings to default. Enter the BIOS (F10), navigate to Power > Thermal , and ensure the fan settings are appropriate for your setup.

An info page will usually open in your browser. Look for a link labeled "View Contents of DOS Flash Folder" inside that folder (typically including a file) directly to the root of your FAT32 USB drive. Do not copy the folder itself , only the files. HP Support Community Step 2: Flash the BIOS HP Compaq 8000 Elite SFF Bios update - HP Community

Select the USB drive; the PC will locate the update files and prompt you to proceed. Method 2: Using HP Support Assistant