Hi @dennispius,
Is there a pattern to the blinking?
Count the number of blinks each light shows and also what colour they are.
There is a pause between the blinking pattern and then it is repeated again.
This is an error code so knowing the pattern will help to find out what's wrong.
Here's a [https://support.hp.com/us-en/document/ish_1997719-1528356-16|link] that shows what they mean.
Click on "Identify the notebook light or beep code" and then click on the one that is shown by your laptop