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HP Desktop PCs - Recovering the BIOS (Basic Input Output System)

This document is for HP and Compaq desktop computers with Windows.
The BIOS is the first software to run after turning on the computer. If the BIOS on your computer becomes corrupted, the computer fails to start to Windows. The BIOS can be corrupted during normal operation, through environmental conditions (such as a power surge or outage), from a failed BIOS upgrade or damage from a virus. If the BIOS is corrupted, the system automatically attempts to restore the BIOS from a hidden partition when the computer is restarted. This document covers other methods to restore the BIOS if the automatic BIOS restoration does not work.
If you experience any of the following symptoms after restarting the computer, recover the BIOS.
  • Windows does not start and the Caps Lock or Num Lock keys blink, or the computer beeps 2 times
  • Power light or charging light continues to blink
  • A BIOS APPLICATION ERROR 501 message displays
  • The computer stops at a black or blank screen when powered on
  • The computer turns on and you might hear the internal fan, but the display is blank and Windows does not start
For business computers, your company IT department or local IT service might manage BIOS settings. Confirm this if you cannot access BIOS settings or restore the BIOS.

Recovering the BIOS using a key press combination

Many HP computers have an emergency BIOS recovery feature that allows you to recover and install the last known good version of the BIOS from the hard drive, as long as the hard drive remains functional. This emergency recovery feature is separate from the BIOS and is designed to work in the event of a catastrophic BIOS failure.
To recover an earlier version of the BIOS on your computer:
  1. Turn off the computer.
  2. With the computer off, press and hold the Windows key and the B key at the same time.
  3. Still pressing those keys, press and hold the Power button on the computer for 2 to 3 seconds, and then release the Power button but continue to hold the Windows and B keys until the BIOS update screen displays or you hear a beeping sound (usually 8 beeps).
    If the key presses do not work, press and release the Power button, and then immediately, press the Windows and B keys at the same time, repeatedly, until the computer beeps or opens the BIOS update screen.
    The power LED light remains on, and the screen remains blank for about 40 seconds before anything displays on the monitor. You might also hear beeping sounds. Eventually, an HP BIOS Update screen displays and the BIOS update begins automatically.
    HP BIOS Update screen showing a progress indicator
    • If the HP BIOS Update screen displays proceed to the next step.
    • If the HP BIOS Update screen does not display, do one of the following depending on the condition:
    • Computer starts into Windows: The computer starts into Windows if the power button and keys are released too soon. Repeat the previous steps, holding the power button down for 2 or 3 seconds.
    • Power LED light turns off: The computer turns off if the power button is pressed and held down too long. Repeat the previous steps, holding the power button down for between 2 and 3 seconds.
    • After repeated attempts, the HP BIOS Update screen does not open: Your computer does not support this function or it has a hardware problem that is preventing the tool from opening.
  4. After the BIOS is recovered, a Continue Startup button displays and a timer counts down. Click the Continue Startup button to restart the computer immediately, or wait for the computer to restart automatically when the timer reaches zero.
    HP BIOS Update screen displaying the Continue Startup button
  5. When the computer restarts, a black screen displays with a message similar to the following:
    A system BIOS Recovery has occurred.
    BIOS Recovery (500)
    Enter - Continue Startup
    Press the Enter key to continue immediately or allow the computer to restart automatically.
    After restoring the BIOS, if the computer repeatedly displays a message about the BIOS, update the BIOS. Go to Updating the BIOS for more information.
  6. After restarting, Windows might display a message stating that the computer was improperly shut down or that a boot problem was detected. Read and respond to the screens to continue.
If this recovery method fails, use another working computer to create a BIOS recovery flash drive to install the latest BIOS file.

Recovering the BIOS using a USB recovery drive

If Windows does not start, use a second working computer with internet access to download a BIOS update. Copy the update file to a USB flash drive and install it on the original computer.
If BitLocker protection is enabled on your computer, the BitLocker recovery key is required to start your computer after the BIOS update. Windows might need to be reinstalled if you do not have the key or the key is not recognized after the update.

Resetting the CMOS

In some cases the automatic BIOS recovery fails because of corrupted Complementary Metal Oxide Semiconductor (CMOS) data. The CMOS stores BIOS settings. You can reset the CMOS and recover the BIOS.
CMOS reset instructions are specific to the motherboard installed on your computer. Find your computer model number, and then use it to get the reset steps (if available) on the HP Customer Support website. If steps specific to your motherboard are not available, use the generic CMOS reset steps.
  1. Locate the model number for your computer. This number is typically found on a label on the computer or on the box it shipped in. Go to How Do I Find My Model Number or Product Number? for additional options.
    The general or series name on your computer is not specific enough for identifying the correct computer specifications.
    Computer label with the product and model numbers highlighted
  2. On the HP Customer Support website, use the model number to navigate to the product page for your computer.
  3. Select Product Information, and use the drop-down menu to select Product Specifications.
  4. Open the product specifications and expand the motherboard section.
  5. Click the motherboard specifications link, if available, to find the CMOS reset steps. The steps for resetting the CMOS might be called Clearing CMOS or similar.
  6. Go to the next section to reset the CMOS using the specific reset steps for your motherboard.
    If specific CMOS reset steps are not available for your motherboard, go to the Resetting the CMOS using generic steps section.






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