Did F10 ever work???
Is your BIOS up to date, there are some Very New BIOS Updates on the site, personally I would do this first, it may be as simple as that seeing they went to the trouble of issuing two new updates recently?
I wonder if installing the "HP Hotkey Support" would fix it. Check and see if this is Installed. It's under "Software Solutions" at the above link.
Always keep track of what is uninstalled.
Here is what the OP at one of the top hits did, a little different than your issue and I assume the same thread John was referring to with the PS/2 fix. After Updating the BIOS, if it don't work, maybe also taking out the CMOS and Purging with the Power Button will help:
I had to disconnect all USB cables, network cable and power cord. Then I had to remove the new hard drive from the PC, the 2 X 16GB RAM, and the NVIDIA GeForce GT 710 graphics card. I then had to remove the CMOS battery. I then had to depress the power on button for 20 seconds. I think all of this was to remove any latent energy still active. I then fitted the COMS battery, hard drive, the RAM and lastly the graphics card. I switched the PC on. F10 took be into BIOS where i was able to check that the DVD was listed in the boot up option. I inserted the Windows 10 pro operating system in the DVD drive, slected continue from BIOS and hey presto, Windows 10 Pro started installing.
Why it got in such a pickle i don't know. there may have been some static electricity produced when i fitted the new hard drive. PC is as good as new and BTW it's £28 to extend the warranty which i will do. Thanks, Bear.
Edited by pcpunk, 06 August 2018 - 10:31 AM.