My Hp Pavilion h9 1215t quit working during a Windows upgrade and will not start

[rray6]

I was doing a Windows upgrade on my Hp Pavilion h9 1215t desktop and I got a blue screen.  I waited for about 15 minutes and the blue screen did not go away.  I pressed the start button to reboot and now it attempts to boot for about 5 or 10 seconds before shutting off.  After another 5 or 10 seconds it tries to start up again.  This continues indefinitely (try to boot and then shut down and then try to boot, etc).  I have to unplug it to stop it.  Incidentally, I do have the BIOS settings to restart in case of a power failure which is why it continually is trying to reboot.  I tried doing a hard reset several times (unplugging everything including power and holding the start button down for 15-20 seconds) but with no success.  I cannot get into Windows even in safe mode since it only tries to reboot for 5 or 10 seconds.  I am looking for any suggestions to get this computer running again.  Any help will be appreciated.  Thanks.

[BeemerBiker]

Can you boot into the BIOS setup?  Press ESC when you see the monitor start up and run the HP diagnostic if that option exists.

If you can boot into the BIOS (no diagnostic program) then configure the system to boot the CD or USB and put in the windows recover CD or USB.   You can obtain one from Microsoft.

https://answers.microsoft.com/en-us/windows/forum/all/how-to-perform-a-custom-installation-of-window...

Ignore instructions on installing Win10,  just use the download link and read how to setup the USB or burn a CD.

when attempting to get into the BIOS, if you press ESC or F10 too soon it will hang and need to be powered off.

If you cannot boot into the bios there are a few other things to try all involved opening the system up and pulling stuff.