Hello 382,
Welcome to the HP Forums!
I understand you are experiencing that the system fan isn't working properly. This could be a result of faulty hardware, or a recent software implication. I apologize for the inconvenience but I will do my best to assist you! To start, please follow the troubleshooting in this document: System Fan (90b) error message on startup
Although the title of the document is "System Fan (90b) error message on startup", the troubleshooting steps presented are relevant and effective. I also provided this document because I believe this is the error that you witnessed, though it's possible that is isn't the same error. If those steps do not work, here are some other suggestions to attempt: Reducing Heat Inside the PC to Prevent Overheating
If these steps do not work, the hardware is malfunctioning. I would contact HP support, to verify what your options are, or take it to a local repair shop.
You can utilize this website to learn how to contact HP appropriately, based on your region: Contact HP Worldwide
Please let me know if you have any other questions or concerns. Thanks again for posting on the HP Forums. Have a great day!
Mario