Computer Power on but nothing on screen then the power turns off and repeats the same thing

[Hugo_]

My laptop first was giving me a fan error but once I got the part fixed after a few months my laptop wasn't charging after a few days later it charged again now it just shows the Power light on after you press it and then it turns off without turning it off.

[Echo_Lake]

@Hugo_

Thank you for posting on the HP Support Community.
 

Don't worry as I'll be glad to help, 
 

Let's try these steps to resolve the issue: 

Hard Reset: Follow the steps from the link: https://hp.care/2GnkMa8. (Refer to the removable and sealed battery)
BIOS default:(do not skip any troubleshooting steps even if you feel steps are repeating)

1. Turn off the computer and wait five seconds.
2. Press the Power button to start the computer and repeatedly press the F10 key to enter the BIOS setup menu.
3. On the BIOS Setup screen, press F9 to select and load the BIOS Setup Default settings.
4. Press F10 to Save and    Exit.
5. Use the arrow keys to select Yes, then press Enter when asked to Exit Saving Changes?
6. Follow the prompts to restart your computer.

Hope this helps! Keep me posted for further assistance.
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