Laptop off but ventilation on?

I just shut down my laptop and then used a cloth to clean the screen and keyboard. After a few minutes I heard that the ventilation of my laptop went on and has been running since then. But I can't get the laptop on. What should I do?

Has the laptop worked before?

Yes

How old is the model

Sometimes the devices ventilate when they are too hot to protect the chips, but usually immediately after switching off and only briefly remove the battery and remove the cable if the battery can't run until it is empty.

Hopefully you didn't use liquid.

Actually, it's off, too. Unless it's extremely hot, mine also runs for 2 minutes.

I only bought the laptop in August and it's a Lenovo IdeaPad Flex 5, so it's not too old in terms of model either. The ventilation has been running for 20 minutes and I can't remove the battery

Let it run empty sounds like a defect