Thank you for posting on the HP Support Community.
Don't worry as I'll be glad to help,
I appreciate your efforts to try and resolve the issue. If you have already performed the steps from the document- Blinking Lights and Error Codes and the issue persists, it could be a hardware failure.
I'm sending out a private message to assist you with the next course of action. Please check your Private message icon on the upper right corner of your HP Community profile Next, to your profile Name, you should see a little blue envelope, please click on it or simply click on this link: https://h30434.www3.hp.com/t5/notes/privatenotespage
Hope this helps! Keep me posted for further assistance.
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