To access information on how to troubleshoot a computer that doesn't boot up, navigate to the Hewlett Packard website, and click Support & Troubleshooting in the Support section at the bottom of the page. On the support page, click Find Your Product, click a computer type, then a computer model.
Once on the support page of a particular computer model, click Troubleshooting on the left sidebar, then select Lockups & PC Performance in the Category dropdown list. When a second Category dropdown list appears, select Lockups, Freezes, Hangs & Crashes. Depending on the symptoms, click the link for "Error Messages Display on a Black Screen during Startup or Boot" or "Error Messages Display on a Blue Screen during Startup or Boot."