Notebook Boot and Lockup

My wife's notebook has been running well for about 6 years without updating Hardware Diagnostics UEFI or the BIOS, as she hadn't needed them.  Yesterday, she found a problem with her battery.  I did some searching in support.hp.com and found an update for the Hardware Diagnostics UEFI that would enable me to test and, if necessary, calibrate the battery.  I also found an appropriate BIOS update.

Toward those ends, I executed the following tasks this morning:

1. installed v.7.4.0.0 Rev.A of the Hardware Diagnostics UEFI by downloading and executing file sp99005.exe

2. pressing <esc> then <F2> at boot brought me to the Hardware Diagnostics UEFI and the things I tried there worked OK

3. updated the Insyde BIOS from version F.25 to F.28 by downloading and executing file sp96175.exe, and that worked OK

4. started the Hardware Diagnostics UEFI at boot again to start the battery work

5. noticed a line at the top of the Hardware Diagnostics UEFI screen that indicated the tool was in need of an update

6. dug around in support.hp.com and found an update for Hardware Diagnostics UEFI to v.8.7.1.0, filename sp141572.exe

7. downloaded and installed the update

8. Now, pressing <esc> then <F2> at boot brings me a blank black screen that does not respond to any of the keys I try and doesn't time out after 10 minutes.  The other items on the <esc> menu at bootup (F1, F9, etc.) work OK.

I have been unable to find any information in support.hp.com that would allow me to uninstall Hardware Diagnostics UEFI v.8.7.1.0 and revert to the v.7.4.0.0 Rev.A which was working.  I attempted the following:

9. attempted to re-install v. 7.4.0.0 Rev.A by executing file sp99005.exe

That attempt failed with an error message that said I couldn't install it over the newer version that was in place.

I also attempted to use the Windows 10 Control Panel and Windows 10 Settings | Apps to uninstall Hardware Diagnostics UEFI, but it does not appear in either place, so can't be uninstalled from there.

I need to get Hardware Diagnostics UEFI working so I can troubleshoot the battery issue.

Thanks in advance for any assistance.