my system sometimes will not display but has light on keyboard. it also hums instead of booting

[princessezinnwa]

my system sometimes will not display but has light on keyboard. i removed the battery and replaced it and the system started making a serious humming noise so i powered it down. after 3 weeks i put it on and it booted but showed. The system time is invalid. This may be a result of loss in battery. Set the correct time and date using your operating system, if this message persist  you may need to replace the onboard battery. Real time clock power loss (005) Enter reboot the system. For more information please visit www.hp.com\go\techcenter\startup

[Meghana_10]

Hello @princessezinnwa, Welcome to the HP Support Community.
 

We understand your concern. Based on the issues mentioned, we would like to suggest a few steps that could help you resolve the issue. Before we proceed with the steps could you please provide us the laptop name and model number so that we can assist you further.
 

Please try the following troubleshooting steps:

Step 1: Verify the RTC/CMOS Battery Installation

Since both the battery and system clock are inter-related, we request that you please provide us the model number to provide you the battery details.
In the mean time you can refer to this link - HP PCs - Resolving diagnostic errors that are displayed during startup | HP® Support

Step 2: Laptop not booting or no display

Perform a Hard Reset

1. Turn off the computer.
2. Disconnect the AC adapter.
3. Remove any external devices (USB drives, printers, docking stations, external monitors, etc.).
4. Press and hold the Power button for 15-20 seconds.
5. Reconnect only the AC adapter and attempt to start the computer.

 Load BIOS Default Settings

If the system boots:

1. Repeatedly tap F10 during startup to enter BIOS Setup.
2. Select Restore Defaults or Load Setup Defaults.
3. Save changes and exit.
4. Set the correct date and time and restart the computer.

Try with an external monitor to confirm if the issue is with the display or monitor

Step 3: Humming noise and Laptop not booting 

This can be related to hard drive or the Operating System

Run HP Hardware Diagnostics

1. Power on the PC and repeatedly tap Esc.
2. Select F2 - System Diagnostics.
3. Run:
   • System Tests
   • Extensive Memory Test
   • Extensive Hard Drive/SSD Test
4. Note any failure IDs or error codes displayed.

Have a great day!