HP EliteBook Power Issues
If you encounter an HP EliteBook that is having power related issues (not powering on) or battery related issues (battery not detected) there are a few steps that you can follow to possibly resolve the issue.
You can perform a hard reset on the EliteBook series laptops by removing the battery, unplugging the AC adapter, and holding the power button down for 30 seconds. This will drain all of the power from the system. You can then plug the AC adapter back in and also insert the battery. If the system still will not power on, a support ticket will need to be created for repair.
Battery Not Detected
Typically the issue is with the Bios not detecting the smart chip in the battery. Once BIOS has properly detected the smart chip in the battery, the battery will be recognized and the unit should no longer have this problem. The solutions below will usually resolve the issue.
1- Remove and insert the battery 6 or 7 times. If this does not resolve the issue, please proceed to solution 2.
2- Update the BIOS. This can be done by going to http://www8.hp.com/us/en/drivers.html and putting in the model and Operating System information to retrieve the most rercent BIOS update.
If neither of these steps resolve the issue, a support ticket will need to be created for repair.