Hello syswombat. I understand you are experiencing a System Error 90b. This could be a result of faulty hardware, or a recent software implication. I would like you to follow the troubleshooting in this document: http://h10025.www1.hp.com/ewfrf/wc/document?cc=us&lc=en&docname=c03620929
If the issue is not resolved, please contact HP for further assistance. Their options will be based on the warranty status of the computer. If you do not have this information, you can locate it at this website: http://h20566.www2.hp.com/portal/site/hpsc/public/wc/home?ac.admitted=1384280905804.876444892.199480143
You can utilize this website to learn how to contact HP appropriately, based on your region: http://www8.hp.com/us/en/contact-hp/ww-contact-us.html
Please let me know if you have any other questions or concerns.
Mario