Try a hard reset and check if that resolves the problem.
Disconnect the charger if connected and then remove the battery from the laptop. Here's the ifixit [guide|125073] guide that shows how.
''Press and hold the laptop's Power On button for a full 30 seconds and then release it.''
Reinsert the battery into the laptop, connect the charger and try turning the laptop on.
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=== Update (07/16/2022) ===
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Hi @fpfp ,
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OK you may have to remove/reinsert the RTC battery from the motherboard and try it again.
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The RTC (Real Time Clock) battery maintains the BIOS settings when the laptop has been turned off. When the battery voltage gets too low sometimes the BIOS can become corrupted preventing a normal start so the laptop doesn't even start or it won't pass POST (Power On Self Test) before it boots into the OS. If it had passed POST there would be the laptop manufacturer's logo on the screen before it boots into Windows and you get the Windows logo.
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Removing the RTC battery (as well as the main battery) ensures that the BIOS will be reset back to its factory default settings when sometimes just removing the main battery doesn't.
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Here's an image from the [link|https://mans.io/files/viewer/235343/1#navigate_bar|maintenance and service guide] for the laptop that shows what to do. It's a bit involved because you have to remove the motherboard to get to the battery.
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Once you have removed the RTC battery from the motherboard, measure the battery voltage. If it is <2.5V DC replace it. It is a CR2032 non rechargeable Lithium battery that is commonly available everywhere e.g. supermarkets. It has a lifespan of about 5-6 years. ''Note: Take notice of which way the battery is inserted before removing it so that you reinsert it (or a replacement) the correct way. Usually it is +ve on top as marked on the battery.''
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After you have reinserted the RTC battery, reassemble the laptop, reinsert the main battery and try turning it on.
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It it still won't start then there is a problem on the motherboard, but one step at a time.
Hi @fpfp
Try a hard reset and check if that resolves the problem.
Disconnect the charger if connected and then remove the battery from the laptop. Here's the ifixit [guide|125073] guide that shows how.
''Press and hold the laptop's Power on button for a full 30 seconds and then release it.''
Reinsert the battery into the laptop, connect the charger and try turning the laptop on.