When I run HP PC Hardware Diagnostics I get a message "No hard drive installed".

[HN770]

The pc went "blind"   when I was trasferring data from one external hard drive to another external hard drive without the power cable connected. Upon start I get the "Bot device not found 3F0" message. When continuing  with HP PC Hardware Diagnostics I get a message "No hard drive installed".

[Echo_Lake]

@HN770

Thank you for posting on HP Support Community.

Don't worry as I'll be glad to help, I have a few troubleshooting steps we could try to fix the issue:  

Procedure 1: Run diagnostics to rule out other hard drive issues. (do not skip any troubleshooting steps if you feel steps are repeating) 

1. Start or restart the computer.
2. Press F2 repeatedly during start up to enter the HP PC Hardware Diagnostics UEFI utility.
3. Select Component Tests > Hard Drive > Quick Test.
4. Select drive C:.
5. Click Run Once.
6. Once the test completes, results are displayed on screen.
   
   If the drive passes all tests, continue to Procedure 2.
   If the drive fails any of the tests, write down the failure ID (24-digit code) and contact HP Customer Support for further assistance.

Procedure 2: Ensure Legacy Support, under Boot Options, is DISABLED.

NOTE: If legacy boot support is enabled, you will NOT be able to see the Intel Optane entry as described in Procedure 3.

1. Start or restart the computer.
2. Press F10 repeatedly during start up to enter the BIOS configuration utility.
3. Check Legacy Support and disable if it is enabled:
   System Configuration > Boot Options > Legacy Support
   or
   Boot Options > legacy Support
4. If Legacy Support is DISABLED, skip to Procedure 3, Step 3.
   If Legacy Support is ENABLED, change it to DISABLED, save the changes and exit, then go to Procedure 3.

Procedure 3. Determine if Optane memory is installed and working normally.

1. Start or restart the computer.
2. Press F10 repeatedly during startup to enter the BIOS setup utility.
3. Look for the Intel(R) Rapid Storage Technology option; navigate to:
   System Configuration > UEFI HII Configuration > Intel(R) Rapid Storage Technology
   
   
   If Intel Optane is not listed, the computer does not have Optane memory or Optane memory is malfunctioning and cannot be detected. Contact HP Customer Support for further assistance.
   If Intel Optane is listed, the computer has Intel Optane memory installed and working normally. Continue with procedure 4.

Procedure 4: Perform F11 Recovery, or restore the system using HP recovery media.

1. Restart the computer and press F11.
   If you cannot access F11 recovery, perform a System recovery using HP supplied recovery media. Refer to the following link for more information.

   HP PCs - Performing a System Recovery (Windows 10)

2. Select Troubleshoot.
   
    
3. Select Recovery Manager.
   
4. Select System Recovery.
   
5. Select Back up your files first (recommended).
   
6. Select Next and follow the onscreen instructions to complete the recovery.

Hope this helps! Keep me posted for further assistance.
Please click “Accept as Solution” if you feel my post solved your issue, it will help others find the solution.