HP Pavilion starts and the lock button flashes. Black screen.

Hello,
After cleaning the fan of my HP Pavilion several times without any problems, the computer worked normally. This time, when I try to turn on the computer, the charge light comes on, and the Caps Lock button blinks indefinitely.
I have tried several solutions:
- Discharging the electrical charge from the motherboard by pressing the power button for a long time with the battery and power cable removed.
- The same with the CMOS battery removed, without results.
- I checked that everything was properly connected inside.
- Both RAM sticks are properly in place.
- I also tried holding Windows + B while starting it up, with no success.

I don't know what to do anymore; everything starts normally, the fan on the motherboard too, and only this Caps Lock light is blinking while the screen remains black.

Does anyone have an idea for a solution?

Thank you so much in advance,

Best regards.