Hello bvsr9791
I am sorry to hear you are having issues with your cooling fan. I would like to offer my assistance in this matter. I am providing you with a link to an HP Support document System Fan (90b) error message on startup which was designed to address the issue you are currently experiencing. I would suggest that you review and apply this document to find a resolution to your cooling fan issue.
I hope this finds you the resolution you are seeking. Thank you for posting on the HP Forums. Have a great day!