Welcome to HP Support Forums. A really great platform for posting all your questions and finding solutions.
I understand that your HP Slate is not powering on at all even though the Power Adapter works and you are unable to perform the Reset again.
This seems to be a Hardware issue.
Please contact our Phone Support for Service Options
1) Click on this link - www.hp.com/contacthp/
2) Click on "Continue as guest".
3) Enter the serial of your device.
4) Select the country from the drop-down.
5) Click on "Show Options".
Fill the web-form. A case number and phone number will now populate for you.
Keep me posted if you need further assistance
Thank you 🙂
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