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HP Desktop PCs - Resolve BIOS ROM or CMOS checksum error

On startup, you might see a BIOS or CMOS checksum error indicating that a Basic Input/Output System (BIOS) test has failed.

One of the following error messages is displayed:


The error that appears depends on the version of the BIOS.

  • BIOS ROM checksum error

  • System CMOS checksum bad - default configuration used

    Press <F1> to resume, <F2> to Setup

  • CMOS Checksum Bad

    Press F2 to Run SETUP

    Press F1 to load default values and continue

  • CMOS Checksum Error - Default loaded

The are two main reasons a BIOS test fails:

  • The battery on the system board has lost its ability to supply power.

  • The BIOS was updated incorrectly.

Restore defaults and replace the CMOS battery

Use the following steps to access the BIOS and apply the default settings to resolve the checksum error.

  1. Turn off the computer and wait five seconds.

  2. Turn on the computer.

  3. When the first screen is displayed, do one of the following:

    • Immediately press the f10 key repeatedly, about once every second, until the Computer Setup program is displayed.

    • Immediately press the esc key repeatedly, about once every second, until the Startup menu is displayed. Then press f10 to open the Computer Setup program.

  4. In the BIOS Setup Utility, select the File tab.

  5. Select Apply Defaults and Exit.

    The computer restarts. If the error no longer appears, you are done.

    Setting the defaults
  6. If the error is not resolved, go to HP Desktop PCs - Removing and replacing the CMOS battery for instructions to replace your CMOS battery.

  7. After replacing the battery, restart the computer to see whether the error is resolved.

  8. If the error no longer appears, wait until Windows opens and set the date and time to current settings.

    If the error is not resolved, the default BIOS information has become corrupted. The computer requires service or a new system board.