On startup, if a system problem occurs, you may encounter a variety of error messages. These error messages provide you and the HP Service technicians with information about what might have gone wrong with the hardware or software on the computer. If the error involves a hardware failure, the system generates a warranty ID code that validates the failure conditions for the customer support representative.

If a computer with the Unified Extensible Firmware Interface (UEFI) environment does not start up, or displays an error message during the startup process, see the following troubleshooting documents.

• For Notebook PCs:

  HP Guided Solution - No Power or No Boot Troubleshooting Boot Device not Found Hard Disk Error HP Battery Alert HP BIOS Application Selected is Corrupt or Missing Invalid Serial Number

  Network not Found (PXE Error) SMART Hard Disk Error System BIOS Recovery has Occurred System Fan (90F) Error Message on Startup System Fan (90b) Error Message on Startup

• For Desktop PCs and All-in-Ones:

  LEDs Blink or the Computer Beeps Boot Device not Found Hard Disk Error HP BIOS Application Selected is Corrupt or Missing

  Invalid Serial Number Network not Found (PXE Error) SMART Hard Disk Error System BIOS Recovery has Occurred System Fan (90b) Error Message on Startup

If a computer does not start, or displays an error message during the startup process, see one of the following documents:

• For Notebook PCs:
  HP Guided Solution - No Power or No Boot Troubleshooting
  HP Notebook PCs - Computer Does Not Start (Windows 8)
  HP Notebook PCs - Computer Does Not Start (Windows 7, Vista, XP)
• For Desktop and All-in-One PCs:
  HP PCs - Computer Does Not Start (Windows 10, 8)
  HP PCs - Computer Does Not Start (Windows 7)

Unified Extensible Firmware Interface (UEFI) is firmware code from a chip on your motherboard that provides extra functionality, beyond the Basic Input/Output System (BIOS). UEFI is a way to do things with your computer before an operating system is loaded. UEFI can provide extra graphic menus and system information on a computer, and basic diagnostics on both a computer and a tablet.

For more information, see About UEFI and the Startup Menu.