Someone may find this useful in diagnosing their HP or Compaq laptop boot failures that generally just show a black screen.
| LEDs blink 1 time | CPU | CPU not functional |
| LEDs blink 2 times | BIOS | BIOS corruption failure |
| LEDs blink 3 times | Memory | Module error not functional |
| LEDs blink 4 times | Graphics | Graphics controller not functional |
| LEDs blink 5 times | System board | General system board failure |
| LEDs blink 6 times | BIOS | BIOS authentication failure |