HP ZBook 17 G5 Maintenance And Service Manual page 126

Performing a hard reset might fix the following common conditions:
Windows stops responding.
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Computer stops before Windows loads, indicated by incomplete boot-up, blinking cursor on a black
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background, and errors relating to operating system not found or a missing drive.
Display suddenly goes blank and stays blank.
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● Software freezes.
● Keyboard stops responding.
The computer does not exit Sleep or Suspend state.
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An external device stops responding. Turn off the power to that device in addition to performing the
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steps in this document.
Before performing a hard reset, you must disconnect or remove all peripheral devices. You should start and
test the computer by itself, and if the problem is not resolved, reconnect one peripheral device at a time. To
resolve the startup or operational problem, run HP Support Assistant, or manually install all updated drivers
from Microsoft and HP.
Before beginning, turn the computer over and look for a battery compartment door (service door). For 2015
platforms, the battery is considered removable but not accessible. See the battery section for how to remove/
unplug the battery.
To perform a hard reset on a computer with a sealed or non removable battery, use the following steps:
1. Turn off the computer.
2. Remove the computer from any port replicator or docking station.
3. Disconnect all external connected peripheral devices such as USB storage devices, external displays, and
printers.
4. Unplug the AC adapter from the computer.
5. Disconnect the battery.
6. Press and hold the power button for at least 15 seconds to drain residual power.
7. Reconnect the battery and plug the AC adapter back into the computer, but do not connect any of the
peripheral devices.
8. Press the power button to turn on the computer.
9. If a startup menu appears, use the arrow keys to select Start Windows Normally, and then press the
Enter
10. After reconnecting each of the peripheral devices, run Windows Update and HP Support Assistant to
update all device drivers.
Clear CMOS
CMOS refers to the battery-powered, semiconductor chip located on computer's system board. Notebooks
store low-level settings like the system time and hardware settings in CMOS. Sometimes it is necessary to
clear CMOS, which requires removing and reinserting the 3V RTC battery for a short period of time (a few
minutes before reinserting), in addition to removing the AC adapter and battery.
114 Chapter 7 Troubleshooting guide
key.