Hi there,
I found some information that may be able to help you.
First, I recommend following the steps listed here: https://support.hp.com/us-en/document/c04052020#c04052020_reset-off
Charge the tablet for at least half an hour, and then disconnect the charging cable from the tablet.
If you have a microSD card installed in the tablet, remove the memory card before resetting the tablet.
Select your tablet model from the list below to view instructions for resetting the tablet
Once you have followed these three steps, try following the steps on this page to reset your device: https://support.hp.com/us-en/document/c03915683#c03915683_resetpoweroff
Please note that these are the steps to factory reset your device. A factory reset will remove all data that is stored on the device. It will not however remove data that is backed up on your Google account, this is recoverable. A factory reset may be the right option however since the device will no longer boot back up.
Hope this helps!
I am an HP employee